Originally posted by ManuH That's not the actual reason. The reason why FF is better in low-light and always will be by about 1-1/3 stop is because it has more area to collect light. Simple physics.
Pixel density is what it is all about, and technological advances.
Many preferred the Eos 5D to Eos 1Ds Mark II, as it was felt that it had better high Iso performance.
The Eos 1Ds Mark II had :
16.6 million Effective pixels
Pixel density 1.9 MP/cm²
Eos 5D had :
12.7 million effective pixels
1.5 MP/cm² pixel density
The Canon EOS-1D Mark III had :
10.1 million effective pixels
1.9 MP/cm² pixel density
Though the 1D Mark III had smaller sensor, and higher pixel pitch than Eos 5D, the high Iso was better, due to newer technology and built to higher level performance.
If you cramp a FF sensor with extremely small pixels, then e.g. an APS-H sensor will be better, if it has larger pixels.
This is why 5D Mark II and A900 means nothing to me, since what really interests me in FF is the road that Nikon has gone with D3, D700.
And also the reason many current 5D original users, were disappointed that Canon had gone MP race with the new model.
Of cause if you downsize your high MP camera, then you minimize noise problems. This is why my K10 with 10.0 million effective pixels and 2.7 MP/cm² pixel density, is great; up to a certain size enlargements.
Else I don't really care too much about it. These things have been discussed so many times. As it is mostly theoretical problems.
Originally posted by Digitalis correct me if i'm wrong, things may hae changed in recent years. I seem to recall Medium format digital backs don't have microlenses. because when they are used in conjunction with large format systems where camera movements like shift and tilt are used microlenses cause disturbing colour shifts at extreme settings.
thanks, very interesting