Used 5DM1 vs 50D

The same FOV reflects how we use FF in real world photos such as by moving closer with the same focus-length lens said 85L, or by using longer lens as in landscape such as 24mm on FF vs 15mm on crop.

With the same FOV, then 50D or even 18mp 7D lose pixel density advantage to crop magnification (enlargement) as 18mp with even as good lens as 100L/2.8 IS macro have not overcome crop penality from crop magnficaiton. They probably will be overcome by 24mp APS-C with a nice resolving lens such as 100L. Again DXOMark test will show the truth. 15mp 50D and 18mp 7D/60D will have pixel density advantage if you shoot from the same distance (then 50D ha narrower FOV) in the case when you unable to move closer or have long enough lens such as in remote birding case.  No mention 5Dc is still noticeble better in SNR than 50D and even 7D/60D.  That's why I have to apply NR on my 60D photos even at base ISO 100 to remove grains/noises in shadow areas.

Many confused amount of pixels simply as "resolution" without considering the most important factor - crop factor. That's why I used 41mp Nokia 808 as an example. If you simply judge by amount of pixels, you'd have to suggest Nokia 808 beats all 5D and even Nikon D800

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