Alpha 700 as a 6 megapixel DSLR…

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I’m still testing the Alpha 700 and still struggling with aspects of image quality, notably the failure to get much wow factor from straightforward shots in good light. It seems easy enough to get exceptional high ISO images, of the type they are expected to be, but even then many examples seen are marred by a very coarse noise structure.

A thought struck me while sitting at my desk. Why not shoot Extra Fine JPEG only? It has already proved to be about as good as the best possible raw converters are managing, until new converters appear. Why not use the 6.4 megapixel image size, 3104 x 2064? This is a shooting option on the camera. For high ISO work, very few people need anything bigger than a 6 megapixel image. It’s the meticulous still life or landscape scene at ISO 100 which really needs 12 megapixels. Action shots, candids, natural light snaps at home can all survive pretty well with 6.

So I set the camera to 6.4 megapixels and snapped what happens to be sitting next to me on my desk, by lo-energy fluorescent bulb.

With some colour correction and a setting of 50 Chroma noise NR in Adobe ACR (which opens JPEGs and can do useful things like this), I have got some 100 per clips from ISO 3200 snaps taken with the 28-75mm f2.8 (D) lens almost wide open. If anything was going to show watercolour effect or noise smearing, it would be the differential focus from this lens. I tried Normal NR, High NR and Low NR all in sequence.

Here are the results. First, Normal NR:

JPEG 3200 normal NR

If you were told this was a 6 megapixel camera shooting at ISO 3200, 1/80th at f3.2 by room light, with colour noise only cancelled in software PP and no further luminance NR, you would probably agree the detail preservation is good, the noise structure looks like film grain, and the unfocused image is rendered without posterization or ‘watercolor’ effect.

Now for High NR – maximum noise removal in the camera. Surely this will mess up the file?

High NR 3200 6 megapixel

Well, it’s not some extreme difference, is it? It is a little softer but those vertical lines on the side of the CD box and the fine narrowing lines of the old Minolta logo are still pretty well rendered.

Now for minimum noise reduction – expecting a snowstorm?

Low Noise Reduction

To me it’s got a bit more midtone noise. Really, if this the degree of difference present between the user controllable NR settings of the Alpha 700, no-one is going to damage images either way (excess noise or excess softening) by getting it wrong. However, remember, these are images made using the camera’s 6.4 megapixel file size. They are not the same as full 12.24 megapixel images, or the same as these sampled down later on. The camera has a pretty good JPEG algorithm, and I have used -3 sharpness for these files. That also helps reduce noise.

I’d say that some very fine detail at 6.4 megapixel filesize has been retained in this shot, looking at the hairline scratch over the a of the word Maxell.

Set like this, the camera will shoot over 300 images on a 2GB card. While you can only get 8 frames at 5fps shooting Extra Fine JPEG full size, I got 34 frames before I thought the rate hesitated a tiny bit – but it would probably have picked up again. At 6 megapixels you can have your Dynax 7D back again, with excellent 3200 ISO performance, 5fps for 30 and more frames, and pleasant noise structure without NR smearing the image into those watercolor blurs. Even the bokeh (so easily lost with the extreme NR effects) is natural.

All this proves nothing in general, it’s just me experimenting a bit while writing other stuff, but it should give A700 owners something to think about. Don’t always use the full resolution. Some have been complaining that we did not need 12 megapixels. Well, you don’t have to have it. The camera will reward you for choosing 6.4 megapixels instead.

– David Kilpatrick

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