Theres no camera from Sony that would be king of low noise. :D But A900 is very usable and easy to clean up to something like ISO 1600 (3200 and 6400 is digital gain anyway, unless you have D3s). Best thing about A900 is colors and color accuracy (which is highest of all dSLRs) plus ofc, its 24 mpix. And it has pretty amazing ergonomy. But it doesn have LV or video mode. :D (tho LV is compensated by OVF which is like one in 1DsMK3)
Its not that RD isnt spent on reducing noise. Sony has similar approach to Minolta, color over everything. If you check that one hidden value in DxOmark (
http://www.dxomark.com/index.php/Cam...#measuretabs-7) you will see why Sony is always behind competition in SNR. Cause they are most of the time before competition in colors. Same goes for A77 which has 86 color accuracy in daylight spectrum (just to give idea, 1DsMK3 has same value and along with 1DMK3 its only camera from Canon that has such high color accuracy).
http://www.dxomark.com/index.php/Cam...#measuretabs-7
Hmm...always behind? Their new sensors are kicking ass...
Nikon D7000 .. ofc it has low noise at high iso, but at certain price, that price is colors. A580 has higher noise, but accuracy is 5 points above D7000. Everything is compromise in dSLR (or pretty much in any kind of photography).
There is one help in this department and thats using Capture One for RAW developing, as they have profiled colors for most cameras, and can squeeze something decent even from some crappy mirrorless cams.
For A77, I think issue will be lens. But on other hand if you will have good lens, it will use everything from them.
Elisha is still shooting, Im following his Flickr. Still doing portraits with 7D. :)