Return of Interesting article on DxO about 5D III and D800...

Started Apr 10, 2013 | Discussions thread
Just another Canon shooter
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Re: Return of Interesting article on DxO about 5D III and D800...
In reply to Steen Bay, Apr 13, 2013

Steen Bay wrote:

qianp2k wrote:

With one of the best lenses 100L, we can see both systems are very close but 5D still edges out a little bit.

With a bit lesser lens 85/1.8 (still very good lens), 5D leads wider.  With further inferior lenses, then 5D will further widen the lead.  The result is clear as we have seen from tons of real world photos from respective cameras.

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We can also see that the 7D actually has a higher resolution. The 5D's MTF curve stops at app. 61 lp/mm because it runs out of vertical pixels (app. 61 lp/mm represents the 5D's Nyquist frequency), while the 7D's MTF curve continues to app. 72 lp/mm (on 24 x36mm). The contrast is rather low, but the 7D's resolution is nevertheless higher.

As I said in another thread a few weeks ago, the extinct resolution of the 7D is higher but that is at a very low contrast. In most of the contrast range, the 5D is either equal (despite having less pixels), or wins easily. I am not sure why this should be surprising to anybody. The  crop penalty is real, and the (low) mp penalty is real, too.

BTW, the real test should be at equivalent FL and equivalent f-stops with common lenses. The 5D will win by even more from MTF20 up, until you get to diffraction limited apertures. The 7D will still be able to show some measurable contrast behind the 5D Nyquist frequency.

When you go to high ISO, even to high equivalent ISOs, the advantage of the 7D will be buried in the noise. On the other hand, the 5D is noisier with equivalent ISOs.

Another observation is that DXO (now) shows the 5D to be clearly the winner in the 85/1.8 case. You can reverse engineer this to make the educated guess that their P-mpix score is weighed more towards medium contrast performance.

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