Crop or cram? Pixel density versus the big view…

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Alpha 700 12.2 megapixel APS-C results
The two lenses used on the 700 were the 70-200mm and 18-250mm Sigmas. Since there are no full frame versus crop comparisons to be made, I have added some variations in processing.
First, the 70-200mm Sigma EX DG II HSM at 200mm is not at its best for peripheral sharpness (as in the Alpha 900 crop) but promises to be pretty good on APS-C. It does still show some fine colour fringes, which can be eliminated using Adobe Camera Raw. I have left the sharpness off and used no NR, but to be fair to the A700, I’ve set the necessary CA correction (+30 R/G) and Defringe.

Already, you can see that the tighter framing has made me crop into the wicket-keeper. That’s partly a matter of paying attention, and experience. The last time I shot cricket (except for some similar tests last month when the A380 arrived) was 40 years ago with a Pentax S3 and preset-aperture Hanimex 135mm f/3.5! Even so, many photographers would choose to keep the main subject central for AF-module related reasons. Click the pic for the original.
The Sigma 18-250mm HSM proved rather difficult to set to exactly 200mm. This shot ended up at 210mm, the marking simply don’t allow a better guess:

No CA correction has been used here at all, and you can probably see the slight green rim on the wicket keeper’s whites. Remember, this lens is being used just 2/3rds of a stop down from wide open. It’s actually one of the best such lenses (no, the best – by some way). The CA fringes can be cleanly removed in ACR:

This version (Alpha 700 Firmware v4, at ISO 320) has CA corrected but also has Luminance NR 25, Chroma NR 50, and Sharpening 25 with a Radius 1 and the default detail presets for ACR. This is an Adobe Camera Raw ‘processed’ raw from the A700 and you can compare it with the one above, which has these controls all turned off. Again, the pix are linked to full size pBase versions.
My feeling about the Alpha 700 is that the image – regardless of the resolution benefit – is a touch softer than the Alpha 900. This has been my general experience of the two cameras. I moved from the original Alpha 100 to the 700. The 100 was and is amazingly sharp, yielding extra fine detail considering it’s only 10.2 megapixels. The 700 certainly does not have that look; the 900 doesn’t either, but it’s a bit crisper pixel for pixel than the 700.
Here is where the Alpha 380, the least suitable of all three cameras for this ‘assignment’, begins to look interesting…

3 Comments

  • A very interesting comparison……
    Three generations of Alpha – ok, well two and a half, because the A100 was the first generation!
    The improvements in the image quality are quite interesting to note. The A900 has better quality than the A700, but the A380 is possibly the best for a small resolution image. It would be interesting to see the direct comparison (at 100%) between the three cameras, with the same lens at the same settings. I am sure that the 24Mpx A900 will produce better detail in a print or overall image, because of the relatively smaller pixels, but the A380 may well surprise us all.
    Thanks for taking the time to think this one out!

  • Yes, I think the 14 megapixel sensor is up to the quality of the A100 sensor, probably better. It has a better handling of highlight to shadow range, and more subtle colour. The colour is the biggest difference, some will prefer the A100. I definitely think it could be used in a better body, and the complaints made about high ISO noise are not entirely justified. It can turn in very good results at 400 and 800.

  • Hi Davie, good article…
    what is your opinion about this 14MPx CCD??
    Do you think this CCD could be use in a better body??
    Do you think this 14MPx CCD can reach the imagen quality of a100 sensor??

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