Alpha 900 HDR bracketing

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The Alpha 900 – and indeed the Alpha 700 with new firmware v4 – offer a three-bracket sequence at a 2 stop interval to enable HDR blending, usually from static tripod-mounted views. At the Edinburgh Alpha 900 launch, I braced myself firmly against an open window, leaning out over the street, and tried an example hand held.

The 5fps shooting speed means that any shift between frames is minimal; with the 16mm end of the 16-35mm f2.8 Carl Zeiss full frame superwide zoom in use, and the naturally very solid grip of the 900 with its extended right hand moulding and finger well, I was able to keep my sequence perfectly aligned.

Here is the set – I was working with a basic exposure set to +1 because of the very bright sky (the sun is actually coming in over the buildings, as the small green flare patch produced by the complex zoom lens shows):

Normal exposure (bracket sequence frame 1)

Dark exposure (frame 2)

Light exposure (frame 3)

Clearly, my set over-ride was not needed and the set would have been better using untouched auto exposure and straight 0, -2, +2 rather than the +1, -1, +3 it ended up with. The test was more an afterthought as with no tripod to hand, I didn’t expect it to be in register – to my surprise, both sequences I shot when examined were precisely in register.

I won’t show Photoshop’s HDR result from this because it is awful. I used Layers instead and a maximum size soft eraser to give the picture the feel I wanted:

A darker sky would been nicer, to allow some vignetting. As for subjects, this was the only view we had from the press conference room, and then only because I opened a large Georgian window and stepped out on to the ledge. Sony did try to stop this but my colleagues rapidly followed – there was NOTHING else of interest to check the cameras and lenses out on!

Here is a version processed by David Anderson using PhotoMatix Pro – from my small posted samples here, and therefore a bit crude, but showing a better automatic than Photoshop produces:

Is two stops either way enough on a 12-bit capture with JPEGs to standard contrast in the camera? Maybe not. With contrast turned right down, then boosted locally in later PP, it could be OK. Assuming raw shooting, another stop could be retrieved from that sky (and it was not dark enough anyway). I think that 3 frames, 2 stop intervals, is reasonable for HDR capture with a 24 megapixel DSLR. It’s already 175 megs of JPEG + RAW data if you shoot uncompressed .ARW.

Now, I’ve not been posting any pixel peeping stuff from the A900. But here is something, because it fits with the shot. I went out on to the ledge with the 50mm f1.4 SAL lens a few minutes later, and used the profile of the neoclassical decoration for a portrait:

I focused the 50mm right on the eyeball, and the camera handled that perfectly. Here is a 100 per cent clip:

Maybe you’ll say that at 1/60th and f5.6, ISO 200, this was unchallenging – but my single-handed camera hold (using the vertical grip, convenient for this) was hardly the most steady as my left hand was holding firmly on to the window frame and I was leaning as far as I dared. The SteadyShot has apparently worked as it should. Remember, if you are viewing that eye on a 96dpi monitor, you are seeing part of an image 42 x 63 inches (106 x 160cm) in size.

Noise? Well, on the pre-production sample, even ISO 100 JPEGs show some structure. And, indeed, we don’t expect the apparent zero noise found on some brands. That kind of image can only ever be a result of smoothing, as in the real word, adjacent pixels will capture different values even in a defocused image zone.

Let’s just say that the Alpha 900 now equals scanning a 35mm frame using a 4000dpi scanner just as the Nikon ED4000. I’d challenge anyone, working from any film, to show me an equally detailed and noise-free result with similarly fine ‘grain’ from any scan without running massive noise reduction or GEM-type processing.

And wait till you see what this looks like from raw!

This is from Sony Image Data Converter 3 using the same presets as the JPEG and default sharpening and NR, as opened.

This is an early raw export using the latest beta version of Andrey Tverdokhleb’s Raw Photo Processor for Mac OSX, which has no NR and only a simple sharpening control (turned off here). You can already see the extra detail present which the in-camera JPEG suppresses even at ISO 200. Look, particularly, at the sharply focused plane of the dark stone to the left of the eyeball.

I am sure that the final release of the Alpha 900, in early to mid October, will prove that the camera has uses for highly detailed photography which will fully justify the price and the overheads of large file sizes. It will not be for everyone. UK prices are already down to £1995 including VAT (£1697 ex VAT, or $3300 US). WarehouseExpress accidentally advertised for the trade price – similar to the ex-VAT figure but including VAT – for an hour or two before rapidly changing their website.

– DK


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