Compared to...

Studio scene comparison (higher sensitivities)

Whilst the Alpha 900's headline-grabbing 24.6 million pixel count might put it at the top of the resolution tree it does, inevitably, come at a price: despite the large, full-frame sensor, the pixel density is roughly the same as a 10MP APS-C camera, and that means noise is going to be a problem at higher ISO settings. The inherently higher noise, combined with Sony's rather brutal approach to noise reduction, means that the Alpha 900 produces rather disappointing output at ISO 1600 and above.

As the example at the bottom of the page shows, turning the noise reduction off, switching to raw capture and doing some serious post-processing (including cutting the resolution in half) narrows the gap between the Alpha 900 and the Nikon D700 significantly, but there's no getting away from the fact that in its desire to raise the megapixel bar even further, Sony has produced one of the noisier D-SLRs launched in the last few years.

ISO 1600

Sony DSLR-A900	Nikon D700
Canon EOS 5	Canon EOS-1Ds Mark III

ISO 3200

Sony DSLR-A900	Nikon D700
Canon EOS 5D	Canon EOS-1Ds Mark III

ISO 6400

Sony DSLR-A900	Nikon D700

ISO 3200 Processed Raw: Alpha 900 vs Nikon D700

Although the Alpha 900's inherently noisier sensor means that it is struggling to produce usable results at ISO 6400, at ISO 1600 and 3200 the difference between it and the D700 can be reduced if you're prepared to shoot raw and do some noise reduction - and crucially, if you resize the Alpha's output to the same dimensions as the D700 (approx 12.1 megapixels).

That all said, even with some Photoshop noise reduction there's still a lot more chroma noise in the A900's end result, and if you try to get the noise levels down to match the D700 you end up with visibly less fine detail than the Nikon is delivering. And if you go one stop further (to ISO 6400) the D700 starts to pull well ahead of the Sony.

Sony DSLR-A900 Raw (NR Off) Processed using Adobe Camera Raw Plus Photoshop noise reduction and resize to 12.1 megapixels + Unsharp Mask.	Nikon D700 Processed using Adobe Camera Raw (default settings) + Unsharp Mask. No noise processing.