Sony A900 vs Canon 1Ds Mark III

Few days after trying the D3x, I have had the occasion to test the Sony A900, that uses the same sensor of the D3x (but it has a different electronics, so it does not mean it has the same image quality). Many thanks to Alessandra (www.minoltasonyclub.it) who has kindly given me the possibility to make the comparison with her A900!

I have compared the Sony A900 with the Canon 1DsIII. The Sony is much cheaper - it is in the same price class of the 5D2 - but it offers similar specifications, and currently it is the most professional camera that you can get if you have a Sony or Minolta lens lineup. Other than that, A900, D3x, 1Ds3 and 5D2 are the currently the only 35mm cameras that offer a fullframe, 20+ megapixels sensor. The D3x, 1DsIII and 5D2 have nearly identical image quality, so I was curios to see how the A900 compares with the other three: on par, worse, better?

Noise comparison

I have photographed the same scene with the Sony A900 and with the 1DsIII; both photos had been taken with tripod and mirror lock up. The photo above is the test target, and the following images are 100% crops taken from the center. The images had been converted with Adobe Camera RAW 5.2; I did not apply any sharpening nor noise reduction. The Canon photo has been upresized to 24 megapixels.

	Sony A900	Canon 1Ds Mark III
100
200
400
800
1600
3200
6400

From ISO 100 to 400, the image quality is very similar, even though the detail is about the same, in spite of the higher pixel count of the Sony. From ISO 800, the Canon is a little better, even though there is not an huge difference.

It must be said that the A900 photos are about 0.3 stop brighter than 1DsIII photos, in spite of the identical exposure (in other words, the actual sensitivity of the A900 seems to be slightly higher than the declared sensitivity). If you take this sensitivity difference into account, I think it can be said that the Canon 1DsIII high ISO advange is about 0.5 or 0.7 stops - not a big difference.

Resolution comparison

This is another test target I have photographed with both cameras. These are 100% crops from RAWs converted with ACR 5.2; the 1DsIII file has been interpolated to 24 megapixels.

	Sony A900	Canon 1Ds Mark III
100
3200

In spite of the higher native pixel count, the A900 shows about the same detail of the 1DsIII, at low ISO. At high ISO, the 1DsIII actually shows a little more detail and less noise.

Sony RAW file: converters comparison

Even though I always use Adobe Camera RAW, I have been asked to try other RAW converters, to see if they to a better work with the Sony files. This is a 100% crop from the same RAW, converted with different programs. I have tried to replicate the same settings in every RAW converter. This is very important because if you leave the converters on default settings, they will apply different processings to the image.

In my opinion, the results are nearly identical - if the crops were not labelled, I doubt that you would be able to tell which RAW converter I used for every crop!

Do you have comments or questions?

If you have comments or questions about this article, feel free to ask in the Juza Nature Photography Discussion Forum!