Pixel vs Pixel FX vs DX

Started May 5, 2013 | Discussions thread
PK24X36NOW
Contributing MemberPosts: 817Gear list
Like?
Re: DPR samples ;)
In reply to Robin Casady, May 7, 2013

Robin Casady wrote:

PK24X36NOW wrote:

Robin Casady wrote:

PK24X36NOW wrote:

Robin Casady wrote:

Since they are both 24 MP, you wouldn't see much difference when pixel peeking. The caveat being that the lens and focus accuracy on the D7100 has to be about 1.5x sharper than on the D600 if they are capturing equivalent detail. However, the D7100 is using a smaller area in the center, it is less challenging to get sharp corners.

Actually, it is only less challenging to get sharp corners IF the lens you're using is good enough (to resolve the DX corners with the detail at less than half the size as compared with FX better than it can resolve the FX corners with the detail at more than twice the size as compared with DX) - otherwise (i.e., as a rule), you actually get better image quality everywhere with FX, even the corners.

The challenge is finding a lens that is good enough. Mose wide lenses have problems with the corners on FX.

I think you have it backwards, i.e., its tough to find a lens good enough to make the DX corners better than the FX corners. It is only with the best lenses at their best apertures that the DX corners will be better, despite using less of the image circle, due to the much higher demand on lens resolution on the smaller sensor (across the entire frame).

The Nikon 17-35mm f/2.8D AF-S is a good example of a lens that does better on DX than FX. It is very sharp in the center, but on FX the corners suffer from strong field curvature.

The test measurements for sharpness of this lens on a D7000 vs. D4 (same pixel count) on DxO Mark conflict with what you're saying. In fact, even with a D3 sporting 4 million fewer pixels, the FX image quality is still better, even in (and actually in particular in) the corners. At most focal lengths, the only place where the D7000 can match even the D3 is dead center, and then only at the best apertures (f5.6 & f8). Only at 28mm can the D7000 best the D3 (due to lack of pixels on the D3 only), and then only at the best apertures, and only in the center - even at the lens' best focal length and aperture combinations, the corners (in fact anywhere beyond 40-50% from center at f5.6 & f8, respectively) are better on the FX D3 than on DX, even with 4 million less pixels. The D4 with the same pixel count is equal in the center at even the best focal length/aperture combinations, and holds an advantage over an even bigger portion of the frame (again, including the corners).

 PK24X36NOW's gear list:PK24X36NOW's gear list
Nikon D810
Reply   Reply with quote   Complain
Post (hide subjects)Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark post MMy threads
Color scheme? Blue / Yellow