lens - Cameracraft

Using the 10-18mm OSS zoom on full frame

Posted on December 3, 2013 By David Kilpatrick

The Sony E-mount (not FE) 10-18mm f/5 OSS lens can be used effectively on full frame for creative work and within limits for technically more demanding shots. Below, an uncropped A7R shot of the concourse at Abu Dhabi Airport, taken at 13mm setting, f/6.3 with my lens profile as provided below. Check the straight lines in the floor tiling, if you doubt that this lens would be of any use for architecture.

However, you don’t get this without a lens profile, and without due care to limit the focal length to a range of 13 to 16mm – not the full 10 to 18mm. Below, you could get this if you try 12mm straight out of camera…

This is a pretty awful case of vignetting and distortion – as you would expect. It’s from an APS-C format wide angle zoom, the 10-18mm f/4 SEL OSS lens for NEX, used on the Alpha 7R full frame mirrorless body. Early in the launch period of this camera, various far more attractive images appeared on-line using subjects like roads, rail lines, beaches and even shop counters where the lines look straight – rather like that drainpipe – because of where they fall in the shot. As you can see, anything with a horizon near the long edge of the framewould have given a very different impression.

However, Adobe offers a free utility which enables you to make lens profiles to correct vignetting and distortion.

I created a lens profile for ACR/LR using full frame and the 10-18mm on the A7R. The vignetting is such that the profile creator really can’t handle it, and overcorrects the extreme corners as a result. I’ve done f/4, f/8, f/16 at 12, 14, 16 and 18mm focal lengths using an A2 chart; for a lens like this, a much greater working distance and an A0 chart would really be desirable. The link below is to a zip file of the Adobe Lens Profiles I produced – for A7 and A7R, with .lcpp files for final use, and .lcp files for different settings of the 10 18mm I found useful.

10-18AdobeLensProfiles

At 12mm you can probably see the vignetting artefacts in the corners, the magenta corner shift and incomplete correction of the horizon line. You’ll also be quick to spot that the 12mm coverage has been reduced to something much less, lens profiles always reduce the field of view (they can not do otherwise).

The profiler simply can’t handle the degree of sudden fall-off in illumination given by the 10-18mm used on full frame. Manual distortion corrections can actually do a better job. At other focal lengths, the profile I’ve made works well enough, and if the frame is cropped slightly (still exceeding the APS-C area the lens is designed for) it’s possible to get good results and wider angles.

I have sold my Sigma 12-24mm HSM II which was used with the A99, and also sold a Voigltander 15mm f/4.5 I bought to test (zero cost fortunately, as it made a small profit between Gumtree source and eBay destination). The Sigma was not only very difficult to focus using CD, its HSM motor won’t play with Sony CD.

My .lcp full-frame file can be downloaded from:

//www.photoclubalpha.com/AdobeCameraProfiles/ILCE-7R FF (E 10-18mm F4 OSS) – RAW.lcp.zip

Just for good measure, here is an uncropped A7R 13mm focal length shot of the church of Maila Dumpara in Kerala taken to use dramatic converging verticals – which fail terribly unless the lines are properly corrected, the last thing you want in a strong upward angle is lens distortion. It’s very stiff test of any lens to do this. I have left the vignetting uncorrected. I rather like it. Click either this or the Abu Dhabi photo and you’ll get a larger image, about 1000 x 1500 pixels.

Samples produced for a dPreview forum question

There’s been a lot of discussion on dPreview forums of which lenses work on full frame E-mount, as Sony saw fit to put a Disable APS-C crop option in the menus of the A7 and A7R (almost as if they wanted owners to experiment). They have made other welcome changes of a similar kind which I’ll cover in a full review of the camera – which I can not do yet as I have no FE mount lenses for it, and with the current choice and prices, I can see I may never use FE mount lenses on this camera.

So, to answer some questions on dPreview’s E-mount forum, I posted these images and comments.

Here is a ‘native’ uncorrected shot of a local building taken on the 10-14mm on A7R at 11mm, f/10, ISO 100:

View: original size

Here is the result of using the profile, doing a crop and some straighten of slight rotated tilt, and pulling the scale down (with the profile applied, the roof apex is clipped off at the top as the lens has so much distortion its 11mm probably becomes more like 15mm when corrected):

View: original size

I’ve used some clarity and local burn adjustments on the sky to treat the image more or less as I would (except that I wouldn’t actually photograph this building at this time of day, with blinds drawn, etc).

For me, the 10-18mm on A7R with our without the profile correction offers the same options as using assorted lenses on 5 x 4 sheet film. It never mattered whether a 47mm didn’t cover the entire film, you got an image circle and could use whatever part of it you want. At 10mm the image, with the profile used, has strong corner cut-off but the overall circle of usable image greatly exceeds APS-C provided you stop down (f7.1 seems just OK, f/10 is maybe optimum, I’d certainly try f/16 despite fears of detail loss).

View: original size

The red crop mark is square – my ‘Hasselblad SWC killer’, as the classic SWC had just a 38mm wide angle lens. You needed to get an Arcbody with 35mm Rodenstock to go any wider on 56 x 56mm film (6 x 6). With the A7R and 10-18mm at 10mm, you get the equivalent of a 24mm lens. Not a 24mm fisheye on 6 x 4.5 like the widest ever offered by Mamiya… a 24mm rectilinear on 6 x 6.

The yellow crop mark represents a significantly larger area than APS-C (which is actually just a little under the 24 x 24mm square in width). It is shifted vertically, as if the lens was being used as a shift lens. If only the APS-C area is considered, its approximately 16 x 24mm area can be positioned right to the top of the frame, equalling a 4mm rise, or the equivalent of using a 6mm rise on a full-frame PC lens (most actually go to 11 or 12mm rise). There is only one lens made which can compete with this, and that’s the Canon 17mm f/4 TS. Admittedly this is a superb lens and when stopped down to f/11 and used on the 6D (Canon’s most shift-friendly sensor) will blow this result away for clean rendering of detail toward the frame edges.

And then, you can still use the 10-18mm in APS-C crop mode as a snapshot wide angle with pretty much perfect correction (Adobe’s own Sony profile for APS-C), for videos too.

– David Kilpatrick

DK's ramblings, Lenses - E mount, NEX System, Photo Techniques, Sony Digital Cameras, Sony Digital Csmeras, Uncategorized

Free software and a cut-price lens

Posted on October 31, 2013 By David Kilpatrick

You have until November 3rd to grab a free download of a truly excellent utility for Mac OSX, created by DxO Optics Pro software team – DxO Perspective. It normally costs $19.95 (or local equivalent) as an Apple App store download, but they have made it free for a few days. It’s a fully working, standard version with no time limit.

Download link for DxO Perspective from Apple iTunes, free until November 3rd

Here’s what they say:

“DxO Perspective corrects all kinds of perspective problems, even the most complex. Using its Rectangle tool, when a photo contains two perspective flaws, DxO Perspective’s Rectangle tool immediately reestablishes a full-frontal view of the object — essential when shooting a photo of a poster or painting! In 8-point correction mode, DxO Perspective handles even more complex perspectives: the independent placing of horizontal and vertical guidelines provides highly precise corrections on multiple planes.”

We can vouch for that. Here’s the software window with a straight shot, uncorrected, Sigma 12-24mm zoom on Alpha 99 at 12mm.

Now on this example, you have a choice of adding points to correct both vertical and horizontal perspective (four indexes clicked/moved) which I have done if you examine the faint blue lines, and this will produce an extreme result:

However, for this example, you would normally onle correct the verticals and omit the four-square connections. This produces a natural result relative to any other correction method:

This is a 100% correction. DxO Perspective lets you reduce the degree of correction. Here is what they describe as a ‘natural’ look, 75% strength:

I preferred the result between 90 and 95% correction.

You may ask how this differs from Adobe Camera Raw lens correction perspective control, or similar functions within Photoshop (without using special plug-ins). First, DxO Perspective is a stand alone program and does not need Photoshop, it only requires a JPEG to select and work on. Secondly, here’s the result from ACR/LR type correction, kept slightly on the ‘natural’ side of :

The greatest difference is that DxO Perspective makes automatic corrections to the vertical aspect and retains the sense of height, at the same time ensuring that the sky is not compressed.

So, enjoy this free download until November 3rd 2013.

At the same time, from 12.00 midnight Eastern Standard Time on October 31st, B&H in New York announced a drop in the price of the Bower (aka Samyang) 8mm f/3.5 fisheye lens for NEX, MicroFourThirds, Samsung NX, Nikon, Canon EOS, Pentax and Alpha mounts – down to as little as $209 for Alpha or NEX:

Bower 8mm fisheye for NEX – but see below!

Bower 8mm f/3.5 lenses from $209

Buy through this link and you support Photoclubalpha in a small way without paying anything extra yourself (indeed, buy any other B&H item after following this link and it will help us).

Here is some advice. The NEX model is basically an Alpha mount optical assembly with a permanently built in extension tube. We advise you to buy the Alpha version, as this is a manual focus manual aperture unchipped lens – use a NEX to Alpha adaptor, doesn’t have to be the expensive official LA-EA1 as this lens uses none of the connections. Then you have a lens which can be used on two systems.

DxO Perspective does not offer a de-fishing function but we’d make a guess that this would be a likely upgrade to the program in the near future and that’s why they are giving it away. DxO Optics Pro software itself is, after all, famous for the inclusion of lens profiles before any of the other programs (or cameras) got this facility.

– David Kilpatrick

Lenses - Alpha Mount, NEX System, Offers, Software Reviews

RX1 ‘NEX’ coming in October – 2 interchangeable lenses

Posted on September 10, 2013 By David Kilpatrick

Reporting from Perpignan, one of our good friends in the biz was enjoying the usual wine and sunshine with photojournalists from a French agency (or two). Turns out that right now there’s an RX1 with interchangeable lenses, just what we asked for when the camera was first seen at photokina, roaming the night-time streets of Paris in the hands of no small Magnum name.

The body is exactly the same size and the mount is thought to be a modified E-mount with additional contacts to enable the silent leaf-shutter and iris action which is the hallmark of the RX1 as a ‘stealth’ shooter. It’s possible that the RX1-N (not necessarily its name) lenses will fit other E-mount bodies, but existing E-mount lenses won’t fit the new mini-Leica-style body. But it may also contain a focal plane shutter, as there is such a high potential demand to retrofit Leica M and other vintage lenses to a full frame body of this size.

More we can’t say. The two international press agencies testing the camera right now are keeping very quiet – just like the camera. In fact it’s hard to imagine the RX1 becoming as ‘noisy’ when fired as a NEX (and they are pretty silent when first curtain electronic shutter is used). So a completely new, or partially compatible, mount may be involved. It would be quite fun though if it turned out that over 30 years after the end of the Minolta CLE, a decade after the demise of the Konica RF, and fully 55 years after Minolta’s first abortive bid to make a Leica M body system camera… that Sony put a plain old Leica M mount on the front instead.

Whatever the case, we gather only ONE lens has so far been released for trials and it’s probably exactly the same 35mm f/2 as the regular RX1/RX1X. A second lens is due by the October launch window and the informed guess is that it will be between 50mm and 90mm, our bets are on the most attractive Leica-heritage option, a 75mm between f/2.5 and f/1.4 in aperture. Those 75mms would have been far more popular on Leica bodies if the viewfinders had been better designed to use them. With electronic viewing, that problem disappears and there is no longer any need to keep to fixed steps like 35mm, 50mm, 90mm, 135mm.

In the meantime Hasselblad is having fun selling their STELLAR alongside the earlier LUNAR – the Stellar is of course an RX100 (Mark 1) with an exotic wood (eco-friendly, folks?) or carbon fibre handgrip and some funky styling in return for a 50% higher price tag. They’ve even opened a new Hasselblad brand shop in Japan to sell these luxury bits of luggage to connoisseurs.

I’ve been using the RX100II. Strikes me the STELLAR is light years behind before it even got of the launch pad. Maybe there will be a Stellar II by Christmas. Make mine an African Zebrawood grip please.

– David Kilpatrick

Our comments system is not working properly so I’ll add this here:

Our contact was sure it was an RX1-type camera rather than a NEX and that two lenses are involved, one in existence, the second to be tested shortly. There are two test bodies in existence, being trialled by two different picture agencies. However, this is third-hand info – other photographers in the agencies involved were talking about something they had seen in the hands of colleagues, and were in turn overheard by a journalist who is not a hardware specialist, who called me with what he had heard. If this was a full-frame NEX, I think it would have been identified as such and the RX1 would not have been referenced. However, it is also possible that the full-frame NEX (already rumoured) could simply be styled like an RX1. I did ask whether it had an eye-level finder but this was not mentioned and therefore not known. It would be great if it was just a full-frame NEX, able to do cropped images with existing E-mount lenses and to use the LA-EA3 (full frame compatible adaptor for Alpha A-mount lenses. It would also be great if it did turn out to use the near-silent leaf shutter mechanism. Both possibilities are speculation. We’ll know in maybe four weeks’ time.

DK's ramblings, News, NEX System, Rumours, Sony Digital Csmeras

Sigma’s system revolution

Posted on September 24, 2012 By David Kilpatrick

Sigma Imaging, already one of our favourite lens makers, has announced upgrades and new functions for their entire system which will transform the way it works with all the major camera systems.

The new DC 17-70mm f/2.8-4 – DC (APS-C format) lenses have never been given the EX designation, even when they clearly matched the EX specifications. Now the EX name and its exterior finish are both going, replaced by one standard for all formats, and one finish.

The entire Sigma range is being restyled, with a new finish, and the old distinctions between EX DG and other lens ‘grades’ are disappearing. “All our lenses have become what we once called EX”, said Graham Armitage of Sigma UK, at photokina. “The demands made by digital systems with higher resolutions mean we have to produce perfect lenses for all the formats from MicroFourThirds to APS-C and full frame.

“Our greatest breakthrough is in MTF testing. We have designed new MTF equipment, which will be used on the production of new lenses from now on. The MTF testing system we use for development is too slow to be used in production, and we have had our own Bayer sensor based system for this purpose. But it was not proving high enough resolution for new camera sensors like the D800.

“Now we have built our own MTF testing system, based on the 46 megapixel Foveon Merrill sensor used in the latest cameras. This allows a much better MTF tests. It will be used to test the sharpness of every new lens that Sigma manufacturers.”

We asked Graham if this would only apply to expensive professional teles, zooms and specialist lenses. “No, it will apply to all lens types”, he said. “We have been able to use the data from the Foveon sensor based tests to improve the performance of all our lenses.” Because the sensor is true RGB not Bayer much better information about chromatic aberration has been gathered and Sigma is feeding this back into the design and manufacture process.

The new lenses have a robust feel, with machined metal barrel and mount components (a current trend for many lens makers) and a slightly soft-looking matt or silk finish. All Sigma lenses are assembled by hand, in Japan, using traditional construction methods.

But the most exceptional advance has been made inside the new lenses – sadly, it can’t be retro fitted to older ones.

The USB ‘dock in a cap’ has an LED activity indicator and we handled the real thing. This photo looks a bit over-retouched.

All new Sigma lenses will be compatible with a USB-connected dock allowing firmware updates to be made by the user. Sigma has honoured its relationship with users for decades by upgrading the chips inside lenses free of charge whenever the protocols used by camera makers created an incompatibility. Now they have developed a way in which users can do this themselves without the lens having to be returned or ‘operated on’ in a workshop.

“The USB dock will cost about the same as a filter”, Graham told us. I suggested this could mean £50. He indicated I was on the high side. This dock device, which resembles a thick rear lens cap, might be £30 or so.

“It does more than just upgrade the chip”, he continued. “With a PC program, you will be able to change the focusing speed of the lens. All AF systems are a compromise, a balance between speed and accuracy. You will be able to set the lens to suit your working style, increasing the focus speed if you shoot action or improving accuracy if you take subjects like landscapes and portraits.

“All DSLRs have problems with front and back focus. Some cameras offer AF calibration, but not all allow you to have different corrections for each focal length of the zoom lens and for different focusing distances. Using our program, you will be able to calibrate new Sigma lenses for the full range of settings so you don’t get front or back focus at any distance or focal length.

“Not only that, with new telephoto and macro lenses you will also be able to change the distance ranges used by focus limiter switches.”

The new-style 120-300mm f/2.8 – one of the first lenses compatible with the USB programming system, allowing perfect tuning of front and back focus corrections across the zoom and focus distance range.

This function sounds familiar, indeed it’s almost what the new Sony Alpha 99 offers with a restricted range of Sony lenses – on-camera setting of focus range limits. The difference with the Sigma option is that future lenses with a range setting switch can each have their individual far, middle and near limits set and there will be no need to go into camera menus to change the setting when shooting.

Along with Sigma’s recently introduction of nano-type hard coatings which resist water and dirt, their improvements in environmental and dust sealing of lenses, we look forward to testing Sigma products in future and finding them close to the blueprint for the optical design. These innovations draw a line between existing generations of Sigma lenses and the future, as they can’t be fitted to older models. They also take Sigma yet one more step ahead of the camera makers’ own aspirations.

Sigma has always shown the industry what can be done in terms of advanced optical design – often unmatched for many years, with such specifications as the 8-16mm and 12-24mm zooms, the 300mm-800mm and many others remaining unchallenged even by Nikon and Canon. Now they have set out to show what can be done by harnessing a simple standard interface and allowing communication to the lens IC through the contact-pin array.

Finally, Graham showed us the new 35mm f/1.4. “Nikon has done really well with their 35mm f/1.4”, he said. “We thought we would try to beat them with this one. We are hoping it turns out to be the best 35m f/1.4 on the market”. The new MTF testing may yet be proved! I mentioned that Samyang had also done pretty well with a 35mm f/1.4. To that there was no comment…

And then there’s the obligatory picture from any trade show – the man who can’t resist trying to find out what the butler saw, courtesy of the Sigmonster!

– David Kilpatrick

This post has been edited with Sigma’s help on October 3rd. The original reference to Zeiss MTF equipment was incorrect; this is used in design and prototype development, and will continue to be used. Sigma’s own production-line testing system is what’s been updated with new high speed Foveon-based MTF bench.

Accessories - 3rd party, DK's ramblings, Events, Lenses - Alpha Mount, News

Hood-cap for NEX with 16mm

Posted on September 23, 2012 By David Kilpatrick

At photokina 2012, the Taiwanese company Hoocap (www.hoocap.com) showed a neat device for many different lenses and cameras, still in development for a wider range. It’s a combined lens-hood and lens-cap, which can be pushed or pulled to seal off or use your lens. They have models for lenses such as the Nikon 24-70mm f/2.8 – but their neatest model is dedicated to the NEX 16mm f/2.8.

One of the best and most original lens designs ever made, reducing the number of elements to fewer than EVER used before for an 83° angle of view, while maintaining an exceptional standard of resolution and geometric projection – and anyone who claims otherwise either just doesn’t understand what makes a 24mm equivalent lens, has a bad example*, or doesn’t realise just how BAD a typical 24mm Nikkor, Rokkor or Canon is in comparison.

Rant over! *Sony’s QC has been less than flattering to the skills of their optical design team.

Now this is an efficient lens shade for video, and not all that bad for the majority of still images taken in horizontal, landscape composition mode. You can, of course, fit the 18-55mm lens hood to the 16mm lens and it does help prevent the very rare instance of lens flare from a design which is highly resistent to flare.

Unboxing, only they didn’t have a box, just a prototype plastic pack. It was disappointing how few firms at photokina were willing to give us samples of relatively small items. We did not have time to spare, just a day. Hoocap immediately understood what we were doing and offered a sample. They were the ONLY company to do so. In past years, we’ve come back with loads of small accessories and items to write about, but this 2012 photokina has been an impoverished one in more ways than just the lack of square metres of stands.

This is how the Hoocap closes. It does add some bulk to an otherwise tiny camera and lens. You pull the unit from the rear to open the hood. It tends to need two actions unless you are lucky enough to get the pulling action exactly at 90°. It does not risk accidental opening, or closing. The action is firm and positive and exerts no strain on the lens or camera.

In case you think we do not question product design, here’s fault no 1 – if you have the small flash fitted to a 3/5 series camera, it won’t stow down fully. But it does turn off. It simply impedes the closing action of the Hoocap. By the way – we tested the cap with a 49mm UV filter fitted to the camera. It allows space for this.

The second flaw connected with flash is this. Look at the geometry – without the Sony flash extender.

It’s not awful, but this f/16 test shows exactly the area of shadow the hood will cast for a typical party or group shot at home. You really need to remove the hood for flash shooting.

Much will depend on the price, but we like this product. It closes the camera off in a very fast action – clunk! – and opens it almost as quickly. It can also be used on the 18-55mm lens but it’s super-neat on the 16mm.

Don’t forget we have a new photo quarterly magazine – Cameracraft. Please support us by subscribing, Cameracraft directly finances the Photoclubalpha website.

– DK

Accessories - 3rd party, News, NEX System

What the buyer wants – NEX-F3, Alpha 37 and more

Posted on May 20, 2012 By David Kilpatrick

SONY is sometimes accused of not listening to the Alpha or NEX owner when it comes to what features they include in new cameras, and what modifications they offer through firmware to existing owners. There are two points of view on firmware; some criticise updates, saying the product should have been released with the right stuff inside on Day 1 while other praise those makers who issue frequent and valuable firmware revisions because they ‘supporting the product’.

My view is the latter; if I own a camera, I really don’t care much what bells and whistles are added to its successor in hardware as I know the only way to get those is to buy the new model. But I do value firmware updates and I know that far more could be done to keep the firmware of older models in top condition. I guess they would have to issue a new camera manual and don’t want to improve the user interface or add functions not included in the original!

Sony does listen, but it listens harder to new potential buyers than to existing owners. It listens to the untapped market, to the people who buy someone else’s camera instead of Sony. After all, it’s already got the existing owners. It only needs to listen to them as far as the next camera upgrade goes for the proportion who will be likely to change frequently.

The new NEX-F3 is a perfect instance of listen to the unconverted market. They want an LCD which aims forward so they can film themselves; amateurs only get one take for their home porn movies and can be very disappointed to find they’ve cut the important bits off. I am, of course, talking about guitar porn, cookery porn, motorcycle porn and not the other kind…so Sony has made the LCD flip over the top.

They have in addition made this entry-level NEX 3 model use the latest 16.1 megapixel sensor, generally agreed to be the most versatile all-round sensor on the market, and accept the accessory FDA-EV1S EVF which doubles Sony profits on any camera sold, should be buyer decide later they want an eye-level electronic finder. The battery life has been extended by 18% to 470 shots per charge, and if you buy the higher capacity 1300mAh Japanese made third party cells in place of the Sony 1080mAh ones which cost six times as much, you win twice. Except that I’ll bet the NEX-F3 adds another layer of battery compatibility protection, just like the 5N and 7 did. The third party cell makers had to update their stuff fast and warn buyers that they needed a compatible type, people owning older clone cells found they didn’t work in the new cameras.

Since this camera is the first NEX (or any Sony Alpha/NEX) to offer in-camera USB connection recharging, the odds are not just high that clone cells won’t work. It’s what bookies call a dead cert. Being able to use your iPhone charger (just a different cable) or similar USB mains-plug or in-car 5v adaptor cuts down on all the rubbish we have to carry when travelling.

To keep the distinction between entry level 3 and better 5 to 7 models clear, Sony has restrained the video to 50/60i with final 25p (European) or 24p (US) output. The better models offer full 50/60p as their top quality. But Clear Image Zoom is included, which does a pretty good job for the everyday user of providing a 2X electronic converter with acceptable full resolution sharpness. There’s no microphone input and some new software which sounds horrible is bundled – PlayMemories Home. Sony, just because you got to use words like Play, Walk, Memories, Man, Stick, Station and so on in various products does not mean they have to be repeated in child-like product names for all eternity!

Sony has added the pop-up flash from the NEX-7 to the F3. Is this a good idea? I predict some deeply disappointed flashers.

It rises just so high above the camera, and it’s not absolutely identical to the 7; the position appears comparable. The new F3 will be sold with the usual single or twin kit lenses I’m sure, and not so often with the latest 18-200mm LE (lite version E?) zoom which has been launched at the same time. This lens is a direct counterpart to the Tamron 18-200mm VC III f/3.5-6.3 which I’ve been used since early March. Though Sony has stated that the OSS (VC) is not as efficient as the more expensive Sony SEL 18-200mm, my findings using the Tamron are that it’s modified to be very smooth during video as has the AF action, which is less volatile than other SEL lenses.

Now I’m sure this lens will be very popular – the Tamron version is sharp and quite beautifully finished, with Sony’s rubberette dust attractor grip absent and a slick metal barrel skin with broad easily cleaned rubber ribs doing the zoom and focus work instead. Tamron’s £499 lens looks like £699 where Sony’s £699 will look like £299 after you have handled it with bare skin for a few minutes. Sony should issue silk gloves with all their lenses.

But here is the downside of choosing such a lens as your kit zoom for the NEX-7 and presumably for the F3. The pop-up flash just doesn’t clear the lens well enough and to use flash with the 18-200mm you must buy the accessory FVL-F20S flash which lifts the light source high enough the camera to avoid what you witness below.

You may also be unimpressed by the uncorrected complex barrel distortion of the 18-200mm Tamron at close range, demonstrated here by photographing an A2 printout of an Adobe lens correction target. Actually, the Tamron profile included in the latest Adobe Camera Raw does a nearly perfect job of straightening up this lens at average scenic distances. This profile should also work with the new Sony lens. What’s good about the Tamron is that its lens identity is recognised by ACR and the correct profile auto-selected.

What you are looking at above is the shadow of the lens, at 18mm, with the lens hood removed and the NEX-7 internal flash used. It is possible the NEX-F3 will be a very small amount better than this.

Here is what happens if you carelessly leave the lens hood on! An A2 target is much the same size as a two-face close-up wide angle portrait, or a typical pet shot or party shot; times you use flash. The shadow does not get smaller further away, but you can dispose of it by using focal lengths over 150mm. Wow!

In other words, Sony has listened to what the public wants – pop-up flash and a superzoom they can afford – but in such a compact body, with no pentaprism-shaped top to allow a good ‘lift’ when the flash is popped up the result will be more than a few unhappy beginners. That is some shadow by any standards.

The Alpha 37

And so to the second consumer-focused launch by Sony this month, the also-16-megapixel Alpha 37. You can think of it technically as a NEX-F3 in an Alpha SLT format – same ISO 16000 top but with 100 at the bottom thanks to the SLT pellicle mirror, same 5.5fps regular motordrive, similar 450/500 shots per battery charge depending on whether you use the power hungry EVF or the economical rear LCD.

You can see here how much extra height the GN10 pop-up flash gains compared to the GN6 of the F3 or NEX-7. It should clear many lenses even with hoods attached, and may well prove usable combined with the new SAM lens for the Alpha range – a slightly more compact 18-135mm f/3.5-5.6 using a type of SAM motor which is claimed to be silent and which allows DMF. Remember that earlier SAM designs with the audible motor have not allowed DMF and have even been quite picky about exactly how you set MF instead of AF. The presence of DMF in the new lens indicates that the SAM internal motor focusing may be a lot closer to SSM than to some basic flavours of SAM. I like the idea of this lens, 18-135mms can be surprisingly good though the f/5.6 long end maximum may actually be slower than many 18-200mm or 18-250mms when set to 135mm (they tend to be f/5 at that point).

Is it a Tamron? Probably not. Tamron lens locks move forward to lock the zoom action. Sigma lens locks, though traditionally placed on the left side, move back towards the camera to lock the lens. Sigma has flavours of HSM which allow DMF and others, like the HSM on their 18-250mm OS, which don’t. I look forward to reports on exactly how the 18-135mm works and whether its superior SAM makes it a hidden bargain.

And also, of course, whether the pop-up flash casts interesting shadows!

There is not a lot more to say about the A37 except that it shares most limitations imposed on the F3 such as the video format and bitrates, that it has the usual bells and whistles including an auto portrait crop framing mode, and resembles an A55 body size updated to be more ergonomic. It also has an updated A55 type EVF, not to be confused with the OLED Tru-Finder of the NEX-7, A77 and A65 but identical to the A57. There is a spectacle friendly EVF mode, which as far as I can tell reduces the image area to match the A55 (which wastes loads of its screen as a blank surround). The big improvement made by the A57 was to deploy the full area of the 1440k-dot screen instead of using it as a milky luminescent border for a small image. The downside is that spectacle wearers find the full area hard to see edge to edge.

The rear screen is 2.7″ not 3″, since this is a very compact body, and uses the double hinged up/down tilt mechanism without rotation or forward facing options.

I did not expect to see GPS in this model, but after several expeditions with the Alpha 77 I am beginning to doubt whether onboard GPS as provided by Sony is much help at all. There have been far too many entire shoots where not a single frame has GPS data. It is something I find extremely useful but it’s only useful if it works most of the time. It’s odd to see USB charging introduced in the F3 but not present in this model. Lack of communication between product teams?

The pricing of the A37 will be very competitive indeed.

With all these various May launches – NEX-F3, 18-200mm LE, Alpha 37, 18-135mm SAM – there’s clear evidence that Sony listens first to mass market dealers and to potential new adopters of large sensor interchangeable lens cameras, those moving up from compacts. Everyone who has ever passed an Alpha or NEX fitted with an 18-55mm lens to a compact zoom user will know the reaction – that the zoom doesn’t even begin to zoom, by their standards. They can’t believe you can not frame a face from twenty feet away.

All Sony’s advances are geared to making these larger format cameras more satisfying to the upgrading user.

Now we just wait for them to produce 2012’s models designed to keep the upgrading Alpha and NEX user equally happy.

– David Kilpatrick

See B&H story and links for current B&H prices/order info

Cameras (DSLR), Lenses - Alpha Mount, News, NEX System

hireacamera.com invest in Alpha and NEX gear!

Posted on March 28, 2012 By David Kilpatrick

The UK’s top camera and lens hire company, hireacamera.com, has invested in a whole new stock of Sony Alpha and NEX gear right up to the 500mm G – their A77s come with 16-50mm SSMs… here, Guy Thatcher explains their enthusiasm for Sony, filmed at the PhotoVision Roadshow in Edinburgh on Tuesday March 27th.

It’s a 1080p HD video shot on the NEX-7 by David Kilpatrick with no accessories apart from the Tamron 18-200mm DiIII VC zoom, which at one point displays a preference for focusing on the better lit, more contrasty background.

Cameras (DSLR), DK's ramblings, HD Video, Lenses - Alpha Mount, News, NEX System

Sony DT 16-50mm f/2.8 SSM

Posted on February 14, 2012 By David Kilpatrick

I’m about to offend myself. I own this lens, and I know how upset owners of brand new lenses get when someone says it’s not perfect. Well, the 16-50mm SSM is far from perfect and if you know how to check out lenses, you’ll agree should you be lucky enough to own one. It’s a compromise. But I love it.

Here’s the problem; this lens has such soft corners and complex distortion at 16mm and f/2.8 that it makes the NEX’s legendarily reviled* 16mm pancake look like a Super Angulon in disguise. It’s got a curved field at 50mm and stopping down does not always bring distant scenes into perfect focus across the frame. It suffers from rampant chromatic aberration which just becomes a dead-sharp fringe on stopping down. *Not by me!

This shot was taken on a preproduction A77 and 16-50mm. I was not supposed ever to show it. But I know there is no fault with the shot, the pre-release gear was just fine. And I really like the minimum focus, at 50mm, at f/2.8!

Yet it also has exceptionally high central sharpness, great colour and contrast, and a lovely quality to its differential focus. That’s the old traditional English-language term for the context in which people over-use the term ‘bokeh’, and deserves to be revived. With f/2.8 to play with across the entire zoom range, you can use differential focus creatively. At medium settings, 24-35mm, the distortion disappears and the sharpness extends corner to corner wide open. You have to set it to 50mm to lose the edge.

More than this, the 16-50mm SSM is a video-tuned lens. Its natural host camera, the Alpha 77, crops the frame considerably when shooting HD video. The soft corners and even most of the distortion don’t get a look in, they are outside the video area. The standard and 3D pan modes of the A77 also crop out the problems. The focus action and silent supersonic motor of the 16-50mm are ideal for A77 video shooting with active AF (if you want it) during takes. The f/2.8 aperture allows the lens to be stopped down to the optimum f/3.5 used for movies and also for high speed (12fps) mode, and have no issues with aperture shifts if the focal length is changed.

The Carl Zeiss 16-80mm, left, is smaller than the Sony 16-50mm SSM.

After testing the lens, I decided to keep my 16-80mm CZ which is now five years old. It’s not just the different quality of image produced by the CZ coatings and design, or the very slighter better close-up ability (you can’t get quite as close but at 80mm the subject scale is a touch bigger on the CZ – the 16-50mm wins at 16mm, where getting two and half inches closer to the subject makes a real difference). The CZ is lighter, takes 62mm filters rather than 72mm, and is considerably smaller with lens hood size adding to the difference. Working in the field, it is a lens which can easily be held in the hand with fingers free to operate the lens-mount release button, hold a rear cap, or even another lens – the usual juggling of two lenses which photographers get used to.

With lens hoods fitted, the overall relative sizes become more obvious. The SSM lens has an attractive metal front ring, a new trademark of higher-end Sony lenses, shared with the 70-400mm G.

The 16-50mm is at the limit of diameter, shape, balance and weight to be safely gripped with another lens in the same hand, even briefly during the process of swapping over. That’s not to say it is cumbersome, just that the 16-80mm is faster and more secure to work with because it’s that little bit smaller and lighter.

Once on the camera, I have to say I like the overall balance created by the 16-50mm. It tends to help the A77 hang lens-down, a position I prefer with the camera under my left arm and the strap over my shoulder. The zoom action is super-smooth and well damped, and also has a lock which operates at 16mm to prevent gravity-fed creep, and keep the action firm in future.

No creepy zooming – thanks to Royal Mail, and their neat Sony-coloured rubber bands which are a perfect fit to go on the CZ 16-80 and make the zoom action super-smooth and stay put!

My CZ is now well used and over-free in action. A rubber band to go over the front end of the zoom ring is the cure! You can get proper broad Alpha-ish orange silicone rubber ones from Lens Band as well as the free orangey-red ones used in the UK to hold our postal deliveries together. My way of using a rubber band is not quite the same as Lens Band’s method, it goes over the flush seam between zoom ring and lens barrel on the 16-80mm and it doesn’t just hold the zoom, it smooths the zoom action.

The zoom lock on the 16-50mm was missed from the 16-80mm… missed by all owners, that is. The 16-50mm has a type of raised moulded marking. Durable? Maybe not. The similar raised ‘P’ on my A77 mode dial is now a ‘D’ having lost its stalk.

The best shots I’ve got from the 16-50mm are as good as the best from the 16-80mm, but I can trust the CZ more in the 35-80mm range. From 35-50mm the SSM becomes increasingly soft and sharpness towards the edges of the frame can be poor. At first I thought this was only at full aperture, but shots at apertures like f/5 and f/7.1 were affected. I compared my own lens with two pre-production Sony samples I had used months earlier; we were told not to release images taken with these. The degree and type of sharpness loss was identical, enough for me to conclude this is a characteristic of the lens and not a coincidental case of rogue lenses.

Major plus points for the 16-50mm include focus accuracy, which is much better than the 16-80mm on most Alpha bodies. The f/2.8 aperture activates higher accuracy sensors, such as the Alpha 700’s central point and the extended range of the 11 cross sensors of the Alpha 77. When used on the Alpha 580 for live view pre-shot AF, or on the NEX models with the original LA-EA1 contrast-detect AF adaptor, both focus speed and accuracy are optimum.

The SSM lens has an AF/MF switch but no on-lens button control. Direct Manual Focus is supported and unlike SAM (conventional in-lens motor) lenses, the supersonic drive is not damaged by moving the focus ring without engaging MF.

Despite the large area of glass, the 16-50mm is no more prone to flare than the 16-80mm. The new Sony coatings used for this lens (water and oil/dirt resistant, very hard, similar to Nikon’s NanoCrystal) do a great job. And, of course, they are part of the final reason I am keeping this objective. It’s weatherproofed to some degree, as is the Alpha 77 body. Reports vary between dowsing with a bucket of water without harm, to reluctant use in slight drizzle. I think I’ll get myself a Sigma EX DG filter for my lens, as these have the same coating now and they are about the best slim-mount UV filters made for optical quality without paying Hoya Pro1 Digital prices.

Also, with the 72mm filter thread, there seems to be less need for a super-slim filter. The CZ lens suffers from very strong mechanical vignetting at both ends of the scale, producing dark corners at 16mm or 80mm alike. At 16mm, depending on the position of the SSS/AS sensor-based stabilisation, a dark corner can be well enough defined to need cloning out or the image cropping. The 16-50mm SSM has no such issues. Not only is optical vignetting well-controlled, the mount does not create any dark corners.

These dark corners are created by adding vignetting and grads in raw processing. The 16-50mm, at 24mm, turns in great shadow to highlight detail without a hint of flare; 1/50th at f/9, ISO 100, hand-held with SSS – mid-January in the Scottish Borders. When I pulled up to shoot this, a car with two camouflage-kitted big Nikon and Canon multi lens ‘serious enthusiast’ shooters pulled in alongside. They were still struggling with tripods, a kissing-gate, a stone wall, lenses and car by the time I’d got the sunray shot (which disappeared in seconds) and left. I just carry my Alpha 77 – but then, I’m not a ‘serious enthusiast’ and my ideal camera would be invisible and with me all the time. I’m a panda – sees shoots and leaves.

Though Sony owners may be reluctant to admit it, the SSS mechanism can decentre the sensor and if the lens coverage is so tight it barely covers the corners of the frame (16-80mm and 16-105mm both guilty) you can get the occasional asymmetric dark corner. I’ve never seen this yet from the 16-50mm. But when I check the 16-80mm against the 16-50mm using the Alpha 900 full frame finder to examine the image circles, if anything the 16-80mm has more apparent clearance round the extremes of APS-C, with a softer gradation. The 16-50mm has a tight exact circle.

I have also checked the way the 16-80mm and 16-50mm focus as you zoom. Though the CZ is not perfectly parfocal. That term describes a zoom which retains exactly the same focus point, as you zoom. Video and TV camera lenses are parfocal, otherwise, the focus might ‘go off’ during a zoom. The CZ is nearly parfocal, just a touch varifocal. That’s the opposite term, and means a zoom which changes the focus as you change focal length. At one time, varifocal lenses were not actually called zooms; they date back to the 1920s, and J H Dallmeyer’s adjustable telephoto lenses. Konica made a famous 35-100mm f/2.8 Varifocal in the 1970s.

Silent focus, silent A77 camera (almost), 16mm and ISO 800 at f/3.2 – with ACR profile correction. Café society, Hawick.

The 16-50mm is either a perfect parfocal zoom, or so close you will never know. It is possible to focus at 16mm, and zoom in to the subject. This can only happen with very accurate focus, and a parfocal zoom. Try it with the 16-80mm CZ and you will see the image go out of focus, not to mention clicks and jumps in brightness changing as the aperture adjusts (that’s because the CZ is a variable maximum aperture lens, f/3.5-4.5). The 16-50mm can zoom during video, in or out, without losing the original focus point and without any brightness change or aperture adjustment.

Now you may understand why I want to keep this lens even though – unlike some enthusiastic new owners – I find that its sharpness across the field is not actually as consistent as the CZ. It is a far better overall match to the Alpha 77 especially for video work. But in January, I chose the CZ in preference for a week abroad, and I would most likely do so again.

The Alpha 77 (and 65) include built-in correction profiles for this lens. They are so effective that when I first saw JPEGs from it, I thought the geometry was perfect. If you intend to use the lens for JPEG and movie shooting, any criticisms can be moderated. The correction profile can not improve sharpness, and it does change the effective focal length slightly so than you don’t get a true 16mm.

This is a straight-on shot of the Adobe chart used (not this way, shot nine times per full frame) for profile creation and it shows how very bendy the 16mm f/2.8 setting is at this range, the target is A2 size. Click image to see full size.

This is the same, but JPEG with the in-camera correction enabled.

This is the same, with the Adobe Lens Profile I have created and sent to Adobe, applied in raw conversion of the first example. Please note that the Adobe profile applies to shots taken at three times this distance or more – these profiles, like the in-camera profile, are never much good at rigorous correction of geometric targets shot a couple of feet from the lens.

For Adobe Camera Raw, I have made a profile for the lens which covers three apertures (f/2.8, f/5.6, f/11) and three focal length settings (16mm, 24mm, 50mm) between all of which ACR will interpolate correction values. Because the extreme corners of the image go so much out of focus when shooting the target (refocusing ruins the profiling process) I don’t think this profile handles chromatic aberration as well as it could. The profiling program needs a sharp image of the RGB colour channels to work out their relative scale, which is how CA is corrected. Applying 150% CA correction, instead of the default 100%, seems to improve the conversion.

Here is an uncorrected real-life shot on the 16-50 and 16mm, 1/125th at f/9, ISO 200 (click image for full size 24 megapixel view, and note the chromatic aberration at the left end of the shot especially).

This is the same raw file processed using the Adobe Lens Profile I have produced for the lens.

You can dowload from here the 16-50mmA77rawAdobeLensProfile, hopefully it will also become available from Adobe’s user-created download area. Unzip the file to extract the .lcp file, and place this in your Application Support/Adobe/CameraRaw/LensProfiles/1.0/Sony directory. You require Photoshop CS5 to use the profile.

So what is my conclusion? I do not agree with some of the over-the-top reviews including one to be found on the Sony store USA site claiming it’s the best zoom of this range and aperture for any system. It is not, you get more than you pay for (much less than a lens of this specification might cost from others) but not an optical miracle. You get a very well designed optical compromise housed in a particularly good mechanical design. I would compare it favourably with Olympus’s waterproof ‘Top Pro’ range fast lenses for 4/3rds. I think it can claim to match Canon’s 17-55mm f/2.8 and Nikon’s similar lens, I’ve used both and the Sony is rather neater. It’s probably a little better than the Pentax/Tokina 16-50mm f/2.8, which it most resembles but definitely is not related to.

It’s different from the CZ 16-80mm, not better or worse; it has a different mix of good qualities and failings. The obvious competitors are Sigma’s 17-50mm f/2.8 OS and the Tamron 17-50mm f/2.8. The Sigma offers Optical Stabilisation. The Tamron is now an older design, replaced by a new VC stabilised version for other mounts, but still issued without stabilisation at about 60% of the price of their VC versions, for Alpha. It is the lowest-cost option in this range.

The Sony Alpha SSM 16-50mm f/2.8 DT lens is supplied with rear cap, 72mm lens cap, and bayonet petal hood. It does not come with a case or pouch. My lens was purchased ‘white boxed’ – that is, split off from an Alpha 77+16-50mm kit by a dealer and priced accordingly. The lens is only available with the A77, or as a separate item; it is not currently offered as a kit option with the Alpha 65 or other models.

– David Kilpatrick

Check the current price from B&H Photo Video – remember, B&H ship worldwide and for the UK buyers, offer a UK service.

Technical Data (Sony information) amended to remove nonsense

Lens Type : Standard Zoom
Focal Length 16-50mm (35mm equivalent 24-75mm)
Lens Mount Type : Sony A-mount, SSM in-lens supersonic motor focusing, electronic coupling
Aperture (Max.) : f/2.8
Aperture (Min.) : f/22
Filter Diameter : 72mm
Lens Groups-Elements : 13 groups, 16 elements
Minimum Focus Distance : 12″ (30cm)
Distance Encoder : Yes
Distance Scale: Yes
Angle of View: 83°-32°
Non-rotating Filter Thread : Yes
Aperture : 7 blades (Circular aperture)
Lens Weight : 20.4 oz (577g)
Maximum Magnification : 0.2x
Dimensions (Approx.) : 3-1/4 x 3-1/2” (81 x 88mm)

Compare the 16-80mm Carl Zeiss technical data:

Lens Type : Standard Zoom
Focal Length 16-80mm (35mm equivalent 24 – 120mm)
Lens Mount Type: Sony A-mount, in-body motor focusing via mechanical drive coupling
Aperture (Max.) : f/3.5 – 4.5
Aperture (Min.) : f/22 – 29
Filter Diameter : 62mm
Lens Groups-Elements : 10 groups, 14 elements
Minimum Focus Distance : 14.4” (36cm)
Aspheric Elements : 2 aspheric
Distance Encoder : Yes
Distance Scale : Yes
Angle of View: 83°-20°
Non-rotating Filter Thread : Yes
Aperture : 7 blades (Circular aperture)
Lens Weight : 15.7 oz (445g)
Magnification : x 0.24
Dimensions (Approx.) : 2 7/8 x 3 3/8” (72 x 83mm)

Equipment Reviews, Lenses - Alpha Mount

Sony’s Zeiss 24mm f/2 Distagon ZA SSM T* reviewed

Posted on December 28, 2011 By David Kilpatrick

The Sony Zeiss 24mm f/2 SSM Distagon ZA T* is probably the best, or equal to the best, in its class. It may perhaps be the best ever 84° angle fast lens ever made for the general SLR system market, and I would happy to pitch it against any of the current equivalent offerings for medium format digital.

The initial journey with the 24mm f/2 was not one of intensive companionship – I am long past the stage of getting hold of a wonderful lens and then shoehorning all my photographs into that lens’s view just because I love the glass. I’ve been through that phase. I remember when I was 18 and my then fiancée (Shirley – still here!) bought me a brand new 35mm f/3.5 SMC Takumar, my first ever multicoated lens as well as my first new boxed product. I shot almost everything with that lens for a month…

A full-frame Alpha 900 study at full f/2 aperture. Check the sharpness in the central – very limited – sharp focus zone by clicking the image for a full size version.

My review of the 24mm appears in the British Journal of Photography for January 2012 but was written in November, and at the end I comment that I do not think I would buy one. Well, between writing that and publication – after returning the test lens loaned to me by Paul Genge of Sony UK – I placed my order. I sold a set of lenses including a 28mm f/2 Minolta RS and a 17-35mm Konica Minolta D to pay for it.

Check current availability and price at B&H Photo Video (opens in a new window will not lose this page).

Why?

It was partly medium format which persuaded me. I’ve been experimenting with MF digital, first using a Hasselblad with a Phase One P20 and then shifting to a Mamiya 645 AFII with a 22 megapixel ZD 37 x 49mm back. Once you put the Zeiss on the Alpha 900, the image quality jumps to match the level of a similar MF pixel count. And without spending into the tens of thousands you can’t match the angle of view at a higher pixel count.

These two cameras both shoot 22 megapixels over a 16 x 12″ print shape (the Alpha 900 being cropped) and both were current in 2008 – though the Mamiya ZD model was shortly to disappear. And the two lenses have similar coverage.

I looked at the corners of my MF shots on a 35mm lens (nearly identical angle of view) – to be clean, they demanded f/11. And then I looked at the corners on the Zeiss, which are even cleaner by f/4. Finally, I considered what Sony may have in store – 36 megapixels on full frame. Everything I’ve seen from the 24mm – including its performance on the A77 and A55 – indicates it will not run out of resolution even if full frame goes well over 50 megapixels.

Then I had the job of looking back over the Alpha 900, Alpha 55 and Alpha 77 pictures taken with the 24mm, and preparing some comparison shots. This was when I realised that my normal line-up of zooms, no matter how good, never got the same from any camera – APS-C or full frame – as this CZ prime. It may be bulky, take large filters, and cost nearly £1,000 but no other solution on any format from NEX through A77 to MF offered the same as the 24mm on Alpha 900. You will, however, be surprised later on to see just how well the tiny NEX 16mm f/2.8 does in comparison when both lenses are stopped down to f/8.

The 35mm 2:3 format shape offers a bit of vertical composition ‘rise or fall’ potential compared to to 3:4 shape of my Mamiya with 35mm wide–angle. Beyond this, the 24mm offers both CD and PD focus with different adaptors on the NEX system, and smooth near-silent AF during video on the Alpha 65/77 and future models. It’s both future-proof and a future classic.

Photojournalism or architecture

Because the 24mm has a fast f/2 maximum aperture, it’s seen as a choice for news, documentary, reportage, sports, and close quarters party or family shooting. Though a little vulnerable because of its size, it does this job well. Unlike tele lenses, any mark on the front glass of a wide-angle like this will show in pictures when the aperture is stopped down. Special care should always be taken of retrofocus and fisheye lenses with vulnerable front elements, my own lens will get a Sigma EX DG 72mm UV filter. Why Sigma? I ran a series of ad hoc tests on filters and these turned out to be just as good as Hoya Pro 1 Digital at half the price, and with better multicoating.

At f/2, struggling with light for a hand-held shot with 1/40th at ISO 1600 on the Alpha 55, the 24mm showed surprisingly clean imaging from the boat to the lights on the cliff top.

Here’s a shot taken at f/2.5, 2/3rds of a stop down from wide open – a sensible aperture to give that hint of extra depth of field and improved optical performance. Click the image to view a full size A55 image on pBase.

When fitted to my A55 or A77, the 35mm-equivalent field of view is also a good general lens for photojournalism (what you get is more or less a Fuji X100 equivalent, but hardly pocketable). The performance over the APS-C field of view is so good that working at full aperture carries little penalty at all except restricted depth of field. The geometry and field flatness over the restricted field mean you could use the lens for artwork copying and get a better result than the 50mm f/1.4 of 30mm f/2.8 SAM macro will produce.

Over full frame, this technical excellence makes the lens attractive to the commercial, industrial and architectural photographer. Whenever you need to apply a strong software correction, focal length figures are thrown out of the window. For example, once the on-board lens correction in the A77 is applied to the 16-50mm f/2.8 SSM lens at 16mm the true minimum focal length equivalent becomes close to 17mm not 16mm.

Hasselblad’s 28mm superwide for its HD series cameras has strong barrel distortion, relying on in-camera and Phocus raw software converter functions to remove it. So while the lens claims to be a 17mm equivalent, that is only true over absolute full-frame 645. On their digital sensors, it’s only equal to a 21mm and the correction means the true crop is more like a 23mm.

A second effect of applying any in-camera or post-process distortion correction is loss of true image pixels. Either you crop the frame after sampling down, or the image is interpolated upwards to fill the frame. Both solutions are far from satisfactory because unlike a fixed interpolation, the value ranges from 0 to whatever maximum is involved (typically between 3% and 7%) and all of this is never a clean ratio.

Above: a sea horizon (the top of the crop is the top of the frame, and it is full width). Top, CZ 16-80mm at 16mm 0n Alpha 77, uncorrected, showing complex wave-form distortion as well as vignetting despite stopping down to f/11. Centre: CZ 24mm on Alpha 900, uncorrected, at f/13. Bottom: 24mm after applying a 2% barrel distortion correction. Click image to view a larger version.

Here the 24mm CZ shines. It really uses all the 24 megapixels of the A900 or indeed the A77, because geometric correction rarely needs to be applied. It has a true 24mm focal length which does not need to be quietly changed to 25mm or 26mm by applying a lens profile. If a 35mm retrofocus AF lens was made for MF digital to this standard, even without the f/2 aperture, it would be hailed as a world-beater. The most that’s needed is a correction of 2% (+, removing barrel distortion) in Adobe Camera Raw and this restores something like a sea horizon near the top of a landscape format frame to a perfect straight line.

No correction is applied here to this full frame 24mm Alpha 900 image – a central horizon, and straight lines which are not parallel to the frame edge, make the 2% distortion (similar to many standard 50mm lenses) no issue at all.

For many subjects, depending on the distance and a ‘rigour’ of the shot (the sea horizon is the most demanding example) no correction at all will be needed. This applies to most interiors, and always to scenes like mountain views or forest landscapes where there is no perfectly flat horizon.

The Alpha 900 is so close to MF digital quality I should really forget the attractions of MF systems. Nearly everything I see from them which impresses me is down to using prime lenses of first quality like the Zeiss and Mamiya 80mm f/2.8 standards and working in a methodical way often using a tripod, minimum ISO, mirror-up operation. Applying the same parameters to Alpha full frame lifts the end result to match – and the CZ 24mm f/2 is a key to unlock that quality.

At f/14, the 24mm is not losing detail sharpness on the Alpha 900 as long as the correct raw processing parameters are applied. To secure this depth of field, f/14 was needed – a medium format camera would require f/27. Holding the camera, viewing and composing this shot were all aided by the ergonomics, weight and viewfinder quality of the Alpha 900. Click image for a full size version on pBase.

This is a dual-purpose or multi-purpose lens. Where the 16mm focal length of the NEX SEL 16mm f/2.8, the Alpha SAL 16-50mm f/2.8, the CZ 16-80mm or SAL 16-105mm all cover the same nominal angle not one of these has the same neutral geometry, even illumination and good corner to corner sharpness at wider apertures. Corrected by software, they don’t have the same true angle and the outer field can become noisy because of extra sensor-mapping gain applied to reduce vignetting.

The size and SEL comparison!

But I would like to show you something surprising. I am a great fan of the 16mm NEX f/2.8 pancake, which is one of the few such lenses made to have a positive (pincushion) simple distortion pattern and a cup not cap shaped field of focus. It is a revolutionary inverted telephoto design of great simplicity, with only 5 elements, enabling the lens to be 16mm focal length yet have a rear node position over 20mm from the sensor – thus avoiding all kinds of vignetting and colour shift problems.

People who don’t understand how to use a focus plane where the corners are focused FURTHER than the centre – the exact opposite of the CZ 24mm f/2 where the corners are focused CLOSER than the centre – do tests like landscapes wide open and wonder why the grass either side of their feet dissolves into blur. Actually all the little 16mm needs is modest stopping down, as would be applied by any professional using a Super Angulon for that matter, to f/8.

First of all, have a look at some lens sizes. I like this shot, as it shows just how big CZ had to make the 24mm to get what they did. It dwarfs the SEL 16mm for NEX and the classic Minolta 28mm f/2 RS:

I’d like you to see the exact comparison between Alpha 900 with 24mm CZ and NEX-5 with SEL 16mm.

This is the A900 and 24mm, entirely uncorrected and uncropped – the building on the right actually does not have a straight wall, don’t be fooled into thinking there’s a sudden burst of barrel distortion! Aperture f/8.

This the NEX with 16mm, corrected in ACR; I’ve tried to keep the camera positions very close but this was real-time shooting and with viewfinder versus screen composition, not so easy. You can see that the 16mm has slightly less true angle of view when corrected but don’t judge from the foreground flower tub, just check the horizontal angle. This is also at f/8.

You can click each image and view a full size JPEG. I have made both of them 24 megapixels, exporting from the NEX to the same size file as the Alpha 900. That may be unfair but you can judge. My opinion is that both the NEX 14 megapixel sensor and the SEL 16mm are underestimated by far too many owners; as far as ISO noise handling goes, the 16mm f/2.8 on NEX is actually as ‘fast’ as the 24mm f/2 on Alpha 900 but that comparison may change with future full frame bodies. As for depth of field, the f/8 shot on APS-C would need to be at f/13 on full frame to match, but in practice both are well covered.

Using the NEX 16mm in different conditions would produce a different result – wide open in a room interior, the corners would be likely to look very blurred. My scene above conforms to the cup-shape focus plane of the NEX lens, and works against the cap-shape focus plane of the CZ 24mm.

Remember as a general rule: barrel distortion = corners focused close than centre. Pincushion distortion = corners focused further away than centre. Moustache or wave form = a doughnut normally of closer focus between centre and corners, but when a full frame lens with this type of distortion (like the 16-35mm CZf/2.8 – or a more extreme example, Canon’s 24-105mm f/4 L) is used on APS-C, you get this doughnut at the corners and more or less have straight barrel distortion not waveform. No distortion at a given distance usually means a flat focus field, the quality which Carl Zeiss highlighted when naming the Planar lens.

Alternatives to the 24mm

The best way to get the 84° coverage with similar near-perfect rendering is to go for the mid-range of a high end zoom. As it happens, Sigma’s 8-16mm is better at 16mm than any of the above-mentioned APS-C options and you can also get a pretty good 16mm from their 10-20mm options and Tamron’s 10-24mm. Tokina’s 11-16mm f/2.8 is weakest at 16mm, best at 11mm. The older Sony 11-18mm is not wonderful at the longer end.

On full format, 24mm at the bottom end of the 24-70mm CZ is no match, it has more distortion and softer corners; 24mm in the middle of the 16-35mm CZ f/2.8’s range is better but with strong complex distortion, more even than the Konica Minolta 17-35mm f/2.8-4 D lens (which manages f/3.2 wide open at 24mm). You might think Sigma’s 12-24mm full frame zoom could be good at 24mm, and perhaps version II HSM when it finally become available for Alpha will prove to be. The original, which I still use mainly for its superb 12mm results, places its worst extreme of field flatness deviation at the image edge when set to 24mm.

I have used Canon’s 24mm f/1.4 USMII and this is faster, larger and more expensive than the Sony CZ lens in almost perfect proportion. Like the CZ f/2 it is a nearly perfect lens, with a hint more barrel distortion and slightly soft extreme corners on full frame wide open. The same goes for the Nikon 24mm f/1.4. I’ve also used Canon’s 24mm TSE tilt-shift and this lens betters the CZ for technical and architectural uses, as it should – so does their 17mm f/4 TSE, which has no match in any format. But such lenses can’t also be used for everyday autofocus image grabbing whether professional or family.

Last question, then. If such a perfect lens can be made at f/2, surely all the affordable 24mm f/2.8 designs could be just as good? We wish! Wouldn’t it be great if the classic Minolta 24mm f/2.8 AF which Sony never transferred to the new Alpha range proved to have the same optical excellence as the CZ? It does not. Nor do the Canon 24mm f/2.8, or the Nikon, or anything made by Pentax or Olympus, or even Leica.

The 24mm f/2 used at f/2.8 on the Alpha 55. Try this with a classic Minolta 24mm f/2.8 and even on APS-C you won’t get the same corner to corner even illumination. Here the focus is on the distance, not the tourists – they are also showing a surprising amount of movement at 1/40th. Click the image for a full size view.

This 24mm is the most recent AF 24mm prime lens to have been designed for full format. Zeiss have designed a slightly more complex manual focus 25mm f/2 Distagon for Cosina partnered manufacture, available for Canon and Nikon, since Sony showed the 24mm at photokina 2010. But Sony’s full-frame DSLR rivals, Canon and Nikon, have not gone for this sub-£1,000 RRP ‘moderately fast’ 24mm niche.

If there’s one competitor, it is Sigma’s excellent 24mm f/1.8 EX DG, which uses a larger 77mm front diameter glass unit to reduce vignetting to the absolute minimum. Distortion is higher, and the lens at present has no HSM version. This makes it less future-proof for Alpha system owners, and also less compatible with NEX and with video shooting in general.

Features of the 24mm

Because it’s a fixed focal length, the 24mm is a very plain lens – it has only two controls and one moving ring. There is an AF/MF switch, though unlike SAM lenses this lens can always be controlled from the body. With SAM type lenses (built in non-supersonic focus motor) it is essential to use only the lens switch, and never to use the body switch instead while leaving the lens set to AF. This is because any attempt to focus manually may damage the gears and motor unless the switch on the lens is specifically disengaged.

Manual focus or held focus can be set or toggled using the single on-lens button. New Alpha models like the 77 allow a wider range of functions to be assigned to the lens button, which is described in the menus as a Focus Hold button. Direct Manual Focus is also supported on bodies which offer DMF, meaning that once focus is confirmed and locked by your pressure on the shutter button, you can fine-tune focus by eye before firing.

The manual focus action is very smooth and well balanced, not too light and not too short in throw (which can be an issue with shorter focal lengths. The focus scale is minimal, behind a traditional Minolta-style clear window, with a depth of field indicator to the minimum f/22 aperture. Really, such markings mean little today as we expect so much from higher resolution sensors. It is time that Sony, and others, built parameter-governed DoF calculation into firmware.

Here, f/5.6 was judged to be fine for the degree of differential focus wanted – at ISO 400, by tungsten kitchen spotlights and window light mixed, on the Alpha 77 hand-held with SteadyShot and manual ‘peaking’ focus.

The CZ design is clearly corrected for medium distance work but retains its performance for close-ups. Unlike Sigma’s design which achieves 1:2.7 image scale, or the new manual Zeiss 25mm which focuses down to 18cm and 1:4, the Alpha lens focuses to 19cm (actually, I make it 18cm as the scale goes beyond the 19cm marking) and manages a 1:3.4 image. Don’t be fooled by distances! The front element of the CZ is already 12.2cm from the sensor plane, and the lens hood takes another 3cm or so. The actual clearance when shooting at close range is minimal. For comparison, the SEL 16mm f/2.8 for NEX will only focus down to 24cm, and the front of this lens is only 40mm from the sensor, leaving a clear 20cm between camera and subject. The Nikon and Canon f/1.4 designs are limited to 25cm and are, quite simply, nothing like as useful for close-ups as the CZ.

You might think that the 16-50mm f/2.8 or the 16-80mm CZ could match the combination of wide angle and close focus found on the 24mm – but not so. To get similar close-ups even at a 24mm setting is not possible – an extra 6 or 7cm in minimum focus distance, when you are talking an 83-84° angle of view, makes a big difference.

Moving in to minimum focus, the bottom wing of the lens hood was only 1cm away from the subject – under 19cm from bread roll to sensor, but only 6.8cm from bread roll to front element. At f/3.2, a hand-held 1/40th was needed (the closer you get, the less you can rely on SS to handle speeds like 1/15th). Focus peaking again enabled the manual focus point to be precisely judged. Great bokeh too.

With a non-rotating front thread, 72mm is one of the classic Minolta sizes. It is necessary to use slimline filters, as with the 20mm f/2.8. It’s interesting to compare the revived older lens with the newer one. The 20mm has only five mount contacts, being non-D specification where the 24mm has eight and reports much more accurate focus data. The 20mm has no lens button, uses screw drive focus, and has a close limit of 25cm at which it has a 1:7.7 image scale. There is also a considerable difference in the build and feel of the CZ; I have no doubt it contains some plastic, but it feels like a good solid piece of engineering and is stated by Sony to have a metal lens barrel. Not metal-skinned plastic, like NEX lenses.

As for coatings, Minolta’s legacy was a use of multiple layer (super achromatic) coatings to rebalance both the contrast and the colour transmission of the entire AF lens range (except designs made by third parties, like the 100-400mm APO). This advantage over other makes was never capitalised on, and made some Minolta designs seem lower in contrast than competitor’s equivalents. No-one ever complained about the colour though! Zeiss’s path from 1975 onwards was to use multicoatings a different way, maximising contrast and light transmission but permitting each lens design to have its own colour transmission quality and variation in contrast. Contax RTS lenses were always praised for their resistance to flare and their extreme macrocontrast.

Since the advent of digital, both overall contrast and colour transmission have become less critical – no need for packs of filters to balance lenses for repro purposes, no need to test Kodachrome with a clip-test to set this up. Just post process or shoot a WB card to taste. Also, Sony Alpha lenses are made in many places – the old Minolta unit, the new CZ-Sony collaboration, co-developed with Tamron and apparently also with Sigma, built by Shanghai Optical or some other owned and partnership facilities in China, made in Thailand but not apparently any more in Malaysia…

While distortion associated with viewpoint and perspective perception is always a companion to shorter focal lengths, over the field of the Alpha 77 (equal to a 35mm lens view or so, in full-frame terms) shapes and solids look natural. At f/4, and ISO 1250, I’ve chosen to downsize this 77 file to 3600 x 2400 pixels (click the image to open). This still allows you to see how clean the light sources in-shot are, with absence of colour fringes. Depending on conditions 1 pixel CA cancelling may be needed with the 24mm.

So, we have here a lens with a Zeiss design and a T* coating which is entirely unlike any Minolta legacy design and will surprise those used to the way ex-Minolta lenses perform. It is fairly immune to flare, not entirely so when confronted with bright sources just outside the image margin, but without the strings of coloured patches associated with 24mms and light sources in the shot. It focuses silently and at a speed which means you may not notice it.

The lens itself weighs 555g, and at 76mm length and 78mm diameter it’s smaller than the 16-50mm f/2.8 SSM which weighs 22g more. I’m not a big fan of lenses you can not clasp in one hand while also operating the lens release mount of a camera; optics this size and weight are about the safe limit. You can not compared the lens-juggling friendliness of the 28mm f/2, for example, with either the 24mm or 16-50mm and even the 16-80mm zoom is much easier to handle in the field. It’s best to remove or fit the hood before changing the lens, don’t leave it in storage position.

The hood reverses over the lens neatly. The whole item, when in this configuration, is a bit large to handle for safe and secure lens changing.

The finish is lustrous, with rubber rib grips that collect dust and dander readily. The supplied lens hood is surprisingly flexible plastic, with a slight spatter finish to the exterior and a kind of semi-flock paint on the inside. It is efficient, but a poor fit with a not very firm bayonet locking action. It’s easy to get the alignment wrong and it’s not as firm or solid as most other Sony hoods. The rear lens cap is still the frustrating one-orientation only design inherited from Minolta, which leaves even those with a quarter of a century of lenscap-fitting experience fumbling for the correct position.

There is of course a Zeiss front lens cap and you get a free blue badge on the lens itself!

Format, pixel count and cropping

For many years when using film I found wide-angle zooms were not essential, standard zooms were useful, and tele zooms were vital. Generally, with any wide-angle you can zoom with your feet or by doing little more than leaning forward or back a bit. Either that or you simply need the widest lens you can get. Whenever I fit my Sigma 8-16mm or 12-24mm on their respective formats it’s the 8mm or 12mm end which is needed. I only end up zooming in if for some reason I decide to leave the lens on, and move to a different situation without time to switch lenses.

With film, you could crop and enlarge. Small pixel count DSLRs made that difficult or impossible – when you are trying to make 6 megapixels do a full page magazine image, cropping is not an option. Zooming in to fill the frame every time became vital from 2000 to 2008 when the first full frame 24 megapixel models arrived.

I think that 24 megapixels has finally made cropping an alternative to zooming. You may need 9 or maybe 12 megapixels, or if you are shooting entirely for the web you may need no more than 2 megapixels. Fixed focal lengths of exceptional quality, sharp all over the frame in the plane of focus, start to be useful. It has never been a good option to crop wide-angle zoom shots asymmetrically, using just one corner. With a lens like the 24mm you can crop any composition out of the high resolution frame and it will not look so different from an on-axis shot with a narrow angle lens.

Lens resolution really does count, as I have found. For three years I used the Alpha 900 with a range of lenses, including the 24-85mm Minolta RS I keep for convenience. When working with medium format lenses on adaptors, I could see that zooms while ‘sharp enough’ usually came nowhere near realising the potential of the 900. Then, using the 24mm, I saw the same pixel-level sharpness pop out. After a month using the 24mm (kindly loaned by Paul Genge) my ordered Alpha 77 finally arrived. I had already seen how the 24mm got the maximum from 16 megapixel APS-C, and this was followed by discovering its power to do the same at 24 megapixel APS-C.

A standard Sony leather-look lens posing pouch is supplied.

How far can this go? If Sony’s 24 megapixel APS-C sensor formed the basis for a full-framer, it would be a 60 megapixel monster and match all but the most expensive medium format image sizes. I believe the 24mm CZ could go there if Sony chose to.

And that, in the end, is why I changed my mind about owning one. The hour or two of useful daylight and howling gales outside have not allowed me to make much use of it yet – but this is a lens for the long term. And for tomorrow’s Alphas as well as today’s.

– David Kilpatrick

Footnote: added February 2016 – I’m now selling this lens, as I don’t think Sony is likely to produce an A99 model II with functions that will restore what I want to have (notably, GPS – they are most likely to drop this). I’m looking at a move to native FE-mount lenses and probably the 25mm f/2 CZ Batis, even though it’s weaker for close-ups, vignetting and distortion.

Here is a recent example of a full aperture shot on the A7RII with LA-EA3 adaptor –

http://www.pbase.com/davidkilpatrick/image/162677066

DK's ramblings, Equipment Reviews, Lenses - Alpha Mount

Tamron 18-200mm VC for NEX

Posted on December 8, 2011 By David Kilpatrick

Tamron’s has announced a high-power zoom for Sony’s NEX-series – the 18-200mm F/3.5-6.3 Di III VC (Model B011).

The image-stabilised lens has exactly the same nominal specifications as Sony’s own zoom. The angle of view is 27-300mm when converted to 35mm format.

It weighs 460g, uses 62mm filters, and has VC (Vibration Compensation). The metallic lens barrel exterior is available in two colors: black and silver. A newly constructed stepping motor allows contrast-detection AF during video shooting. Direct Manual Focus (DMF) allows the user to make fine manual adjustments in the AF focus.

Di III (Digitally integrated design): A new designation Tamron gives to lenses engineered specifically for mirrorless interchangeable-lens cameras with no internal mirror box or pentaprism, adopting an optical design that matches the characteristics of the digital camera.

The result of this development is a lens that is compact and lightweight, featuring a 62mm filter diameter and weighing only 460g. The lens is available in silver and in black.

Tamron’s VC mechanism employs a three-coil system, electromagnetically moving the VC group via three steel balls. The VC lens elements are held in place only by contact with the steel balls, achieving smooth movement with little friction. This provides a stable viewfinder image with excellent tracking performance that eliminates the blur from handheld shots for cleaner, crisper shots.

Tamron’s earlier VC unit has a moving magnet system with heavy magnets in the vibration-compensating lens. However, the new VC mechanism adopts a lightweight moving coil system that reduces the load on the drive system. This allows the drive to be operated with smaller coils and magnets, reducing the weight and size for the entire VC unit. In addition, improvements to software and other elements of the VC mechanism used in the 18-200mm Di III VC have made the mechanism even quieter.

Specifications 18-200mm F/3.5-6.3 Di lll VC (Model B011)

Focal length: 18-200mm
Maximum aperture: F/3.5-6.3
Angle of view3: (diagonal) 76˚ 10´-8˚ 03´
(Horizontal) 66˚ 16´-6˚ 43´
(Vertical) 46˚ 51´-4˚ 27´
Lens construction: 17 elements in 13 groups
Minimum focus distance: 0.5m (throughout zoom range)
Maximum magnification ratio: 1:3.7 (at f=200mm: MFD 0.5m)
Filter size: φ62mm
Length4: 96.7mm
Entire Length5: 102.0mm
Diameter: φ68mm
Weight: 460 g
No. of diaphragm blades: 7
Minimum aperture: F/22 – 40
Standard accessories: Flower-shaped lens hood (included)
Compatible mounts: Sony E-mount

The angle of view of the lens when used for video on the Sony digital HD video camera recorder NEX-VG10 is 32.4 – 360mm when converted to the 35mm format.

Due to an inherent characteristic of this TAMRON lens, the resulting image in the LCD monitor may be displayed in a “pumping” manner in the continuous operation of the focus search function when using the Sports Action mode on Scene Selection. The actual images captured will NOT be affected by this circumstance. In other Shoot Modes (P, A, S, M), when the focus mode is set to Continuous AF (AF-C), the same condition may also arise. The actual images captured will also NOT be affected by this circumstance.

As an alternative to the above settings, you can change the focus mode to Single-shot AF (AF-S) or Direct Manual Focus (DMF).

This lens was developed, manufactured and will be sold based on the specifications for the E-mount that was disclosed by Sony Corporation under Tamron’s license agreement with Sony Corporation

Price: The suggested retail price is yet to be announced. Availability: Early 2012. Exact date to be announced.

Accessories - 3rd party, HD Video, NEX System

« 1 2 3 4 5 … 7 »