Sigma’s new Sports grade 70-200mm f/2.8 released

The £1499 lens which is relatively compact goes on sale in the UK from December 7th for Sony E and also L-mount. It’s got so many new features that the best way to take them in is Sigma’s own press release, which we offer for download here from 12pm on November 16th, the embargo date.

Sigma 16-28mm f2.8 E and L mount

The companion for Sigma’s highly regarded 28-70mm f/2.8 compact zoom adds an unbroken range down to 16mm while retaining a small c. 77x100mm size, 72mm filter fit, and 450g weight. It is announced today and will be available to buy from June 17th for £749.99 (UK SRP) or $899 (US retail before tax).

The new 16-28mm seen fitted to Sony’s compact A7C, with the companion 28-70mm left. The two lenses together weigh only 920g.

The full-frame Sigma 16-28mm f/2.8 DG DN Contemporary offers a promise of exceptional optical quality with a faster constant maximum aperture in barrel size similar to existing f/4 16-35mm designs. Special attention has been given to field curvature correction for edge-to-edge sharpness, important in wide-angle views – this is enabled through the use of a built-in lens profile, correcting distortion and vignetting in-camera or during raw image processing. 

It uses five FLD (fluorite-like glass) elements and four aspherics to minimise chromatic and off-axis aberrations. The lens has an inner zoom mechanism that keeps overall length and the centre of balance constant, improving performance when zooming during a gimbal take. The 72mm filter thread is larger than the 67mm of the similarly light and small 28-70mm f/2.8 DG DN Contemporary.. At just 100.6mm long (L-mount version) and 450g it’s appealing for outdoor, social, street and travel photographers who want a lightweight outfit for day-long use.

The lens is constructed using aluminium and thermally stable polycarbonate, performing well in temperatures from the arctic to the equator, and has a dust and splash resistant mount. AF uses a proven stepper motor compatible with high-speed AF, DMF and AF or MF modes with an MF switch on the side. It focuses down to 25cm with a maximum image scale of 1:5.6, 0.17X and has a nine-blade rounded aperture. On the L-mount version only, linear and non-linear focus ring behaviour can be set using the USB Dock UD-11.

The lens is supplied with front and rear caps and a bayonet mounted petal lens hood. Sigma WR or WR Ceramic,WR UV and WR Circular Polarising 72mm filters are optional extras.

Sigma UK – https://sigma-imaging-uk.com

Product information – https://sigma-global.com/jp/lenses/c022_16_28_28

Compact metal 20mm f/2 from Sigma

The new 20mm f/2 DG DN Contemporary lens for full frame E and L mounts from Sigma will sell for under £650 in the UK from February 25th. It extends their compact, metal barrel prime ‘I’ series range which includes f/2 models in 24mm, 35mm and 65mm focal lengths.

Sigma I-series 20mm f/2 DG DN Contemporary

It also offers a filter-friendly alternative to the very large and heavy 20mm f/1.4 Art lens. It uses 62mm filters, weighs 370g and is just 72.4mm long (much the same as the 24mm f/2). It has a magnetic lens cap and all metal construction, including the bayonet lens hood. A second plastic clip-in lens cap is also supplied. The design with a physical aperture ring is similar to Sigma’s high-end ciné lenses.

The lens with its hood, seen here in ‘bare metal’ before the black coating is applied to the components.

It uses three high-precision glass-molded aspherical lens elements, one SLD element, and one FLD element. Suppression of sagittal coma flare makes the 20mm f/2 ideal for night sky with stars near the extreme corners of the field. 

Other specifications include:

  • Lens construction: 11 groups, 13 elements
  • Angle of view: 94.5 
  • 9 rounded diaphragm blades
  • Minimum aperture: f/22
  • Minimum focusing distance: 22cm
  • Maximum magnification ratio: 1:6.7
  • Inner focus system
  • Compatible with high-speed autofocus
  • Stepping Motor
  • Compatible with Lens Aberration Correction
  • Support DMF and AF+MF
  • Nano Porous Coating
  • Super Multi-Layer Coating
  • Aperture ring
  • Focus Mode Switch
  • Petal-type lens hood (LH656-03)
  • Magnetic metal lens cap (LCF62-01M)
  • Mount with dust and splash resistant structure
  • Support for switching between linear and non-linear focus ring settings (for L-Mount only)
  • Compatible with SIGMA USB DOCK UD-11 (sold separately / for L-Mount only)
  • Designed to minimise flare and ghosting
  • Every lens checked using proprietary MTF measuring system
  • High-precision, durable brass bayonet mount
  • Made in Japan

For further information:

#SIGMA #SIGMA20mmF2Contemporary #SIGMAContemporary #SIGMAContemporaryPrime #SIGMADGDN #Iseries #SIGMAIseries

Sony A7RIII review in Cameracraft

Read David Kilpatrick’s review of the Sony A7RIII

Cameracraft January/February started the A7RIII test report, and March/April 2018 continued it. Both are free to read here. In the second issue you’ll also find the review of the 24-105mm f/4 FE G OSS lens. In the first issue, Gary Friedman looks at the RX10 series and one-inch sensor quality as well – and David tests the Voigtländer Nokton 40mm f/1.2 Aspherical FE manual focus lens, Sigma 16mm f/1.4 DN DC, and Samyang 35mm f/2.8 AF FE.

Part 1

Part 2



Sony’s precision aspherics

In interviews about the new micron-accurate aspheric lens element moulding process used to increase the resolution of the latest Sony G Master lenses, a visual has appeared which shows the ‘onion ring’ effect that coarser mould machining causes in lens elements.

Working independently, I’ve been aware of this for years – and I have used a point-source photography technique to study lenses. I’m not an optical engineer or scientist, indeed I don’t even have a degree in anything. I came into photography through Victorian books and teenage years experimenting with lenses, developer formulae, building my own equipment and using observation, corollary and deduction to understand how things work. It’s helped me explain difficult technical stuff to many thousands of readers through books and magazines, without using maths or formulae, and very few diagrams.

In the Cameracraft back in 2013 I published a home-brewed rendering of aspheric moulding visual analysis.

Here’s Sony’s visual showing the difference between traditional aspheric moulding (pressed glass aspheric, as pioneered by Leica and Sigma) and their new refined pressing with better engineering.

onion

And here is my home-brewed visual from Cameracraft when I explained the bokeh and resolution issues created by pressed elements (and also, some other aspects of bokeh, which I’ll refer to below the image):

onion-ours

This is the clip from a 2013 article in Cameracraft dealing with broader aspects of bokeh, depth of field, aberrations and how images are rendered. You can download the two-page article here. Nine years after we launched Cameracraft the magazine is going strong, it’s a bit thicker and does have the occasional advert unlike our original, but it is still one of the best ‘never knew that before’ reads a photographer can have drop through the letterbox. You can arrange that easily enough here!

Here is the full article as a downloadable PDF.

Sony’s new superlens was not any better than the Sigma 70mm f/2.8 macro which I still use. My reasons for choosing this macro are simple – it is optically excellent and traditionally made without any aspheric or other special elements, and it uses simple focal extension for focusing, not rear or internal group movement. This means it’s a true 70mm lens even when used at 1:1 and gives the maximum lens to subject distance, for its focal length.

However, it’s MUCH better than the Voigtländer 50mm f/1.4 used for the colour bokeh shift example at the top. Sony’s information makes it clear that the new more precise aspheric moulding allows new surface profiles and the elimination of chromatic aberrations which cause this magenta-green foreground to background shift in so many otherwise excellent lenses. I’ve said that to do so, the new lenses must be what would once have been called Apochromatic, though that term has only ever meant that all wavelengths focused to the same plane and at the same scale. Even past Apo lenses can show poor colour bokeh. It’s interesting that Sigma, after years of plugging the APO (capitals not actually needed, folks!) label chose not to label some new lenses this way even through their performance matched or exceeded earlier APO models. Sony seems to be taking the same view – G Master will be sufficient label to imply very high resolution, elimination of bad colour bokeh shifts, and by implication an apochromatic performance on RGB sensors.

So will I be buying these amazingly expensive, large, E-mount dedicated lenses? Probably not. My unscientific observations tell me there are smaller, lighter, far less expensive lenses which will serve me better. Mirrorless digital camera bodies with high quality EVF and high magnification focusing allow me to  do things I could never have done over 40 years ago when I took my first position as a Technical Editor (of the UK monthly Photography published by Fountain Press and edited by John Sanders). Geoffrey Crawley, editor of the British Journal of Photography, showed me how to evaluate any lens quickly with the help of a light bulb, a darkened studio, a roll of background paper and a sharp pencil. Back then you had to expose film, now you can just look through the finder. In a photo store, any LED spotlight will do for a quick check. Focus centre, magnified to max, at full aperture. Move to all corners in turn without refocusing, magnify each time. Refocus each corner in turn when magnified, examine change in rendering of point source. Buy the lens which shows symmetrical, balanced results and the best sharpness of the corners when the centre is correctly focused. Do this with a light source at least 3m/10ft away and if you can, even further. Repeat one stop down, two stops down, with zooms repeat at three or four focal lengths across the range. Never do it at close distance (hint: lens test chart results are only good for the distance you photograph the chart from, which is why Imatest, DxO and other labs have test targets the size of a wall and industrial sized space to work in).

And, if you have a single LED bulb or miniature LED torch, you can examine any of your lenses in a darkened room and produce a ‘bump map’ which will reveal its moulding defects, scratches or fungus, blemishes, and population of dust and microfauna.

– David Kilpatrick

dk-cameracraft-bokeh

For our PDF and App editions, go to Pocketmags where you’ll find Apple iOS, Android and all the usual choices to subscribe or buy individual editions.

And if you really want a trip back in time – there were huge changes between 2012 and 2015. Cameracraft documents the rise of mirrorless, the growth of hipster retro, and the discovery of older manual lenses as it happened. You can read a full set of the 12 issues via this one-off YUDU subscription:

Click to view the full digital publication online
Read Cameracraft 2012-15
Self Publishing with YUDU

Low-cost macro for the A7 series

It’s been a while since my last review of Sony products here, and not because I have been inactive. The truth is that I’ve spent so much on Sony kit 24/7 working has been necessary, including a good few reviews and tests of the A7RII and lenses appearing elsewhere. It’s a real issue, I now lose so much value with the lightning-fast depreciation of Sony’s products within a few months of launch that my old tactic of buying, reviewing and selling no longer works. For one thing, no media in the world will readily pay a fee which even matches the amount you might lose on a camera body in the A7 series over its first two months of retail life. Sony have been good enough to lend me a few items for brief periods but you really can’t form any useful opinions on such radical and new hardware on that basis.

However, my A7R II report is shortly on the way, and the extra time spent using the camera and suffering the damage to my credit card does not harm the process. It helps put the gear in context. I’ve resisted the anti-social pricing policies of the UK camera retail environment for some time, even buying one grey import from Panamoz. So it’s appropriate that my first article for a fair while should be intended to help you save money and get great results from any A7 full frame FE mount camera, while also supporting a company whose UK pricing policies are entirely reasonable – Sigma.

The Sigma 60mm f/2.8 ART DN lens

The butterfly above is one example of what this lens can do on uncropped full frame, in this case adding a single 16mm extension tube, which we’ll come to later as the exact type of tube you buy matters a great deal!

The neat, low-cost 60mm f/2.8 is the portrait lens in Sigma’s Art DN lens trio for APS-C and MicroFourThirds mirrorless systems. I’ve used the 19mm f/2.8 and 30mm f/2.8 as well, but the 60mm is my favourite. Originally, I tested it on Olympus MFT and the 50cm close focus with their 2X factor made it almost feel like a macro. It’s actually just 1:7.2X scale, but 1:3.6X relative to full frame on that smaller sensor. That’s a really good working distance and subject scale.

I was curious to see how much of the full frame the 60mm would cover. All these Sigma lenses are just £129.99-£139.99 retail at most UK dealers right now. They are beautifully designed and made, very light, use 46mm filters and have advanced optical design giving high contrast and first-class full aperture sharpness. Well, the answer is easy enough; you’ll get more than APS-C, with a 24 x 24mm square format crop working well, but not anything like full frame at any aperture from the 60mm.

This is the closest focus of the Sigma ART DN 60mm on the A7R II, uncropped.

Sigma call it a telephoto, with its rear nodal point much closer than 60mm to the focal plane. But its design signalled it would probably perform well as a macro lens too.

Meike extension tubes

So, we add extension tubes between the A7-series body and the lens. There’s one prominent make, Meike, and a couple of years ago I bought their very low-cost fully electronically coupled plastic 10 and 16mm twin tube set. 26mm of extension is not much. It won’t even make the E-mount 35mm f/1.8 focus to 1:1, and does even less with a 60mm. However, what it does is worthwhile combined with the lens’s own focusing range.

 

I found my plastic Meike tubes have a narrow circular throat and cut the image off all round. But, you say, the image was cut off all round already, so what could be done?

When you mount an APS-C lens on tubes, it covers more than APS-C. Put it on tubes adding about 1.4X to its focal length – like using 26mm of tubes on a 60mm lens – and it will cover full frame. You are moving the lens further from the focused plane, and as you do so, its fixed angle field of sharp coverage grows (it more or less follows the inverse square law, as does the effective working aperture of the lens when you use tubes). So a lens made for the NEX sensors, c.16 x 24mm, can cover 24 x 36mm when used on tubes for close-ups. The 60mm on 26mm of tubes would cover 24 x 36mm even with no leeway. Since the lens already has a good image circle, it turns out that it covers 24 x 36mm when used on the 16mm tube alone, and shows just a hint of corner cutoff with the 10mm tube alone. With both, it covers the full frame easily.

This is the result of using a 10mm metal extension tube – not the plastic set. The plastic design cuts off even more than the lens used on its own.

Meike understand this. They have a newer, metal-mount extension tube set costing about twice as much as the original plastic one. To get it, you must search for Meike metal extension tubes – and they are not easy to identify for certain. There’s very little explanation on-line. These tubes have a full width throat with baffles top and bottom, more or less matching the 24 x 36mm frame shape. Some black flock paper is glued in to prevent light reflection at the sides, but none is fitted top and bottom, and this is the main weakness of the design (you can obtain flock paper and fix this yourself).

Twin set, no pearls

Used alone, the metal Meike tubes turn the Sigma 60mm into a very good close-range long standard lens for the A7 series. I found that you can add the plastic tubes next to the lens, not next to the camera, and suffer no cut-off. This combination of four tubes adds 52mm and makes the Sigma 60mm able to do 1:1 with the addition of its own AF range.

You need to understand sensor-based stabilisation before using any manual lens on tubes (which these are equally suitable for, with adaptors). The A7 II series bodies use the focal length and focus distance of the lens as transmitted to the camera to control the Steady Shot Inside function. As far as I can tell from practical tests, the Meike tubes do not transmit any change to the information reaching the CPU, but SS seems to be OK with such relatively minimal extra focus extension.

This shot was taken at 1/15th hand-held with the 16mm tube on the A7R II, ISO 800, 14-bit uncompressed raw, f/8 on the Sigma 60mm lens. There’s no significant corner vignetting with 16mm of extra extension to the lens.

This is a 100% clip from the shot.

When I mount my 50mm Macro SMC Takumar on the A7R II I use either the SSI menu control, or the Lens Compensation App, to tell the SSI system I’m using a lens with an extension in place. It focuses to 1:2 size, and for this I tell the camera I’m using a 75mm lens not a 50mm. If I add 26mm of tubes, it will focus to 1:1 and I need to tell the camera I’m using a 100mm lens. That’s because a 50mm lens extended to 1:1 focus has the same camera shake characteristics as a 100mm lens used on a distant scene. Be careful, as this relationship only holds good for simple lenses (Tessar, Sonnar etc) and not for any zoom lenses, or any macro lens which uses internal focusing. If you mount a Tamron 60mm f/2 macro on your Sony body using a dumb adaptor, just tell the camera it’s got a 60mm attached. The Tamron changes focal length to focus, but the effect for anti-shake purposes is that it remains a 60mm. Its angle of view remains unchanged as you focus, while my 60mm Sigma when used at 1:1 repro covers half the angle of view it does at infinity.

I am not entirely sure whether the Meike tubes work properly with SS Inside, or if the system simply has enough latitude to function with my degree of unsteady hand-holding. Those contacts just seem to make a connection, with no chip to add information. The EXIF data does show the focal length correctly, and the set aperture (which will be a reduced effective aperture at closer range, 26mm of tubes turns 60mm f/2.8 into a working f/4-ish). But the focus distance is shown as whatever the lens focus function chip confirms – a range of 50cm to infinity. That’s obviously incorrect when tubes are added, in contrast to using a dedicated lens like the Sony 90mm f/2.8 FE G OSS Macro, which will show the true focused distance in the viewfinder and also pass correct data to the CPU.

So, a warning – the 60mm plus tubes is not technically perfect but seems to work well enough.

When you use a tripod or flash, or a fast shutter speed, and turn off Steady Shot none of this applies. In practice with shutter speeds fast enough to stop subject action or wind vibration, it all goes well. The Sigma is very sharp even though not designed for macro range work, but that’s typical of this type of lens – even if 8 elements in 6 groups with several low-dispersion elements is not basic.

sigma60mm-26mmtubes-iso800-A7RII

Here’s an example with 26mm of tubes plus some lens focus range. The ISO 800 14-bit uncompressed file has allowed some work on the bee’s back which lacked contrast. Click to open a 2048 pixel wide version.

sigma60mmf9on20mmtube-iso800-A7RII

Here’s an example which clicks through to a full size A7R II AdobeRGB JPEG (no doubt much crunched by WordPress image storage) taken at f/9 on the 16mm tube. If any of my image files have 20mm in the filename it was the 16mm tube – I’m so used to the lengths used by regular SLR mounts! The 60mm has a seven-blade aperture and gives pleasantly neutral defocused quality behind the subject. You can call it bokeh if you want to. Thank you, Scottish weather, for keeping a few flowers in this condition and giving me some sunshine just after the 14-bit uncompressed raw upgrade for the A7R II arrived.

The Metal Meike extension tubes have the same essential benefit over the plastic version with all FE and E mount, and legacy, lenses used of the A7 series full frame bodies. You can use them on the 28-70mm, 24-70mm, 55mm f/1.8, 28mm f/2 and most lenses though they have little use with the 70-200mm and I would not recommend hanging a 24-240mm off a tube.

Footnote July 2017: I now have the 50mm f/2.8 FE Sony macro. It’s a very nice lens, indeed, but the internal focusing means it’s really more like a 40 to 35mm as you get the subject bigger, and you end up just millimetres away. I compared using this lens on 26mm of tubes to focus on a target 7.5cm wide with the lens itself set to infinity (and therefore, 50mm). Working distance from the lens rim to subject – 11cm. Then I took the tubes out, and focused the lens using its own range, on the same target. The clear distance was reduced to 7.5cm. Now you know why you need tubes and probably don’t really need a macro lens.

– David Kilpatrick

If you have found this article useful, you can support Photoclubalpha by using affiliate buying links (we are not sponsored or paid in any other way, except by selling subscriptions to f2 Cameracraft).

Sigma 60mm at B&H

Vello metal mount extension tubes at B&H (similar to Meike)

Sigma 60mm F2.8 DN for Sony E – Silver from Amazon UK, no idea why they have none in black

Neewer metal extension tubes – much better price than Vello! on Amazon

Visit Wex Photographic and search for any items (UK)

No FE or A mount for new Sigma 24-35mm f/2

We’ve had news of the new Sigma Art HSM high speed wide angle full frame zoom – 24-35mm f/2.

Sigma24-35f2

It will be available in Nikon, Canon and Sigma mounts only (release date not yet confirmed) according to Sigma in the UK.

Note that this will be a bit of monster with its 82mm filter thread, 117mm long barrel and substantial petal lens hood.

Sigma does not make a full frame DSLR. Sony is now a major market for high end full frame lenses. What’s going on here? We’ll just have to wait and see. Maybe Sigma just reckon every FF Sony mirrorless owner will have a Canon AF adaptor and maybe their HSM – which works pretty well on the A7II – will even allow fast AF on the new A7R II.

– David

Sigma launch mount switching service

SIGMA is going to start a new “Mount Conversion Service” which will enable Sigma to convert the mount of customers’ Sigma Art, Sports and Contemporary lenses from one camera fitting to another.

120-300mm-f2.8

The ranges convertible include the new Sports models such as the 120-300mm f/2.8

“We believe that a lens is not only such a key device for photographic expression, but also an important resource for photographers”, they say. “It has been our hope to develop the lens system that is genuinely photographer-centered, and you can enjoy it for a longer period of time. As an experienced lens manufacturer that has been creating a diverse range of interchangeable lenses, our desire and know-how is crystalized in this unique service. With this service, the mount of your SIGMA lenses can be converted to another mount system, depending on the specification of camera bodies. This service will be available from September, 2013.”

Editor’s comment – this feature of the new Sigma lens designs was not even mentioned at photokina 2012. They have kept something under wraps which must have been planned from a very early date. The main lens unit of all Sigmas in these series has to be effectively independent of the mount, with electronic protocol conversion chips to handle aperture and focus operation while different rear assemblies change the bayonet.

“Interchangeable lens camera systems appear to be superior in offering photographers more options, allowing them to change lenses freely and have more flexible photographic expression”, states the Sigma release. “Nevertheless, each interchangeable lens is limited with the specification of different camera systems. In other words, you can’t use those lenses if you change it from one type to another. Although lenses are the key devices to create photographic expression, it is a shame that there is no system that purely sets the standard based on the functions and individual qualities of interchangeable lenses.

“In this circumstance, SIGMA is going to start the “Mount Conversion Service” from 2nd September 2013. Our goal is to provide more freedom for photographers so that they can select new camera bodies without worrying about the conventional limitation around the mount system of cameras, and keep on using their current lenses by adjusting them to fit with a new mechanism.”

For the details, please check the Sigma website http://www.sigma-global.com/en/lenses/cas/service/mcs/index.html * This “Mount Conversion Service” is different from a normal repair. In order to apply for the service, please contact your nearest authorized subsidiary / distributor of SIGMA.

Sigma’s system revolution

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.

Sigma ultrawide zooms – old and new 12-24s versus 8-16mm

For almost a decade the Sigma 12-24mm full frame ultra wide angle zoom has been unrivalled by any other makers – not Nikon, not Canon, not Tamron, not Tokina, not Sony. No maker has ventured where Sigma went, to the extremes of over 120° coverage combined with well corrected straight line geometry.

Today, the original 12-24mm is in its fourth incarnation, having progressed through EX to EX DG (digital) and then with added HSM hypersonic motor focusing, which never arrived for Alpha mount in the original design. The fourth version is an entirely new design, and does have HSM for Alpha. It is very similar to the new 8-16mm design, introduced three years ago for APS-C cameras, which also offers HSM focusing in Alpha mount.

Update five years later, 2017: there is now a constant aperture 12-24mm f/4 ART lens. This is a completely new design and has an almost-perfect performance, especially in terms of corner detail wide open. I’ve tested it in Cameracraft magzine. However, I did not have the various older models to make direct comparisons. The MkII remains available as the current non-ART, lower priced Sigma option.

Here you can see, from left to right, the EX DG 12-24mm f/4.5-56, the DC 8-16mm f/4.5-5.6, and the DG HSM II 12-24mm f/4.5-5.6. Don’t be fooled into thinking the original is wider in diameter, it actually shares exactly the same lens cap module as the new design; it’s smaller and around 100 grams lighter. Both the 8-16mm and new 12-24mm are surprisingly solid items.

First, we’ll look at the difference between old and new 12-24mms. I have used the old one in several versions on several different camera makes. and I’ve never had one which was truly sharp at all point across the frame wide open. The field is not perfectly flat, and autofocus modules are very bad at getting an exact focus at 12mm. Combined with lens mount tolerances, sensor flatness problems (mostly in Canon full-frame, which historically have not had very ‘plane’ sensors), sensor parallelism problems (all makes, Sony not excepted)… it was always a good idea to stop this lens down to f/11.

How bad is that? Perfectly normal for any lens covering over 85°. Even the best large format lenses, single focal lengths like Super Angulons, have always been used in the awareness that full aperture is for focusing and you stop down to between f/11 and f/32 for the actual shot. On 35mm format digital, using anything much below f/16 is counter productive for sharpness and my normal choices on the Alpha 900 have been f/10, f/11, or f/13.

The good news is that the latest version has a different kind of field flatness. The old one tended to have a zone, like a doughnut, of closer effective focus surrounding a sharp middle. At 24mm, where this older lens performed at its worst, this zone was pushed out to the far edges and could result in the corners looking softer than they do at 12mm. The new one has a simple barrel distortion in place of a wave-form distortion, and along with this goes a simple curvature of field.

The bad news is that the overall level of distortion is much higher than the old design. At 12mm, it’s close to needing the fingers of two hands. Adobe Camera Raw had a correction profile for this lens from Sigma almost the day it became available. That profile fixed the distortion perfectly but leaves you slightly less of a 12mm than you’ve paid for, because it reduces the angle of view.

Here are some comparative views. First of all, I’ve used only 10 megapixels of the Alpha 900 frame, cropping from the top of a vertical shot, to get this architecturally correct view. This is like using the 12-24mm as an extreme 12mm shift lens on an APS-C camera. As and when we get a 36 megapixel Alpha full framer, the crop to do so will be more  like 16 megapixels. This is the full frame:

Below you can see the crop used to 10 megapixels, and by rolling your cursor over the image, the change between a profiled conversion and a raw conversion with no lens corrections. On this crop it does not look extreme.

But this is a relatively kind way to use the new lens. Here is an example pushing straight lines into places where extreme wide angles don’t like ’em:

This is an uncorrected 12-24mm DG II HSM shot out of the Alpha 900 at 12mm. It’s not exactly what you want, and in fact, it’s not as ‘good’ as the old design despite being sharper. Hovering your cursor over the image shows the same raw file with the Adobe Camera Raw Sigma-generated Lens Profile (also works in Lightroom) applied. As you will see, straight lines have been restored along with even illumination. But – how much of that 12mm, 122° angle has been lost? Is it now really only a 12.5mm?

In practice, the new 12-24mm gives you a great range of creative choices when confronted with a building. Here is a revisit to the first subject, taken at different focal lengths, getting closer to the building with each shot:

24mm

20mm

17mm

15mm

12mm

When it comes to comparisons with the older design, the new one is much sharper at the edges. It does not need stopping down to f/16 to pull in the worst aberrations, though it does still display some around f/8 to f/11. Here’s an original 12-24mm EX DG design shot (12mm, f/9, vignetting corrected but distortion not corrected):

And here’s the new 12-24mm under the same conditions (small exposure difference due to changing light) processed similarly, without any geometric corrections:

On this shot, the corrugated barn sides have clean ribbing to the extreme ends, with some softening; on the old design, they begin to look a bit of a mess in the outer quarter of the frame.

Trying the 8-16mm extreme

But when doing these tests, I decided to throw a novelty into the mix. What if I put my 8-16m APS-C format Sigma DC HSM zoom on to the Alpha 900? Because it is not an Alpha lens, the 900 does not automatically crop the full frame. This is what I actually got with the lens set to 8mm:

And in Adobe Camera Raw, I just dialled up the Scale in Lens Correction to 146%, which blew up the central 12 or so megapixels of the frame to become a full 24 megapixel image:

And here, for comparison, is what the 12-24mm set to 12mm could produce:

This is a little tighter than the 8mm using the maximum I could get (including some extra image height), so the 8-16mm used this way can produce something closer to an 11.5mm full frame lens. However, I have not yet done the obvious – to get an engineer to remove the petal lens shade from the 8-16mm (it appears to be part of the front element assembly). This would enable even more angle without shading, and the possibility of square or 10 x 8 shape format crops.

What was particularly interesting about this experiment was the quality of the 24 megapixel file extracted from a smaller section of the Alpha 900 sensor by Adobe Camera Raw upscaling. Full size files are available to download for subscribers to Photoclubalpha – it’s well worth the $10 for a full year of access to any of the extras we provide. See the download links at the end of the article, which will become visible if you are a registered subscriber to the site.

The 8-16mm also achieves full frame coverage on the Alpha 900 when set to 16mm, though with fairly marked vignetting:

Here are some more samples from the 12-24mm DG II HSM: first, 17mm at f/8 – no geometry correction:

Next, at 12mm at f/13 which on the A900 seems to be the limit for good detail sharpness without extra effort in processing:

And 17mm at f/22 – beyond the diffraction limit, but processed carefully for detail:

And 12mm at f/9, an optimum setting for detail with plenty of depth of field for this subject:

So, what was my own decision? I own the 8-16mm and an Alpha 77. That’s what I use for travel and general work. I own an original EX DG 12-24mm. I decided not to buy the new 12-24mm because I concluded that the 8-16mm used on APS-C was effectively as good. The angle is not quite a match for the 12-24mm on full frame, as APS-C is not a true 16 x 24mm. For those occasions where a 12-24mm on full frame is needed, I’m nearly always able to work on a tripod at f/13 and focus manually (which overcomes most of the issues with the earlier lens). Since it needs less drastic geometric correction, it offers a very small angle of view advantage over the new lens in return for the risk of poor sharpness if not used well stopped down. I have no doubt the new lens is better, but it’s not £400 better which is what the ‘trade-up’ would cost – and the old lens is lighter and smaller, which I appreciate.

The test made me even happier with the 8-16mm, especially with the thought that some modification could make it a unique lens to use on the Alpha 900 or a future full frame EVF model (A99). After doing these tests, I decided it was not necessary to take the Alpha 900 and a 12-24mm despite the investment in two weeks’ shooting in the Sierras and Pacific Coast of California – the A77 and 8-16mm would do everything I needed.

But for those buying a 12-24mm, for full frame on any system, the new Sigma represents even better performance than the 8-16mm (better edge and corner sharpness at one stop down from wide open) and has none of the failings of the older lens even if it does need more post-process geometry correction.

Download full size images [private] 24 megapixels 12-24mm EX DG at 12mm f/9 Download Link
Download full size image 24 megapixels 12-24mm DGII HSM same as above Download Link
Download full size image 24 megapixels 8-16mm lens scaled to 24 megapixels from A900 ‘crop’ Download Link
Download full size image 24 megapixels 12-24mm DGII at 12mm compared to 8-16mm at 8mm cropped Download Link
Download full size image 24 megapixels 8-16mm at 16mm filling full A900 sensor Download Link
Download full size image 24 megapixels 17mm f/8 fence example shot boat Download Link
Download full size image 24 megapixels 12mm f/13 sequoia tree example shot Download Link
Download full size image24 megapixels 17mm f/22 boat Download Link
Download full size image24 megapixels 12mm f/9 riverside tree Download Link [/private]

To check the weight, specifications and other details of these three lenses we suggest you visit Sigma’s own site – for the new 12-24mm, here’s the UK site info. And here is the 8-16mm, which they oddly don’t class under wide zooms, but under DC lenses.

You can check worldwide shipped prices from B&H Photo in New York.

– David Kilpatrick

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