That would only be the case if the CoC was larger than what I chose as acceptable. With such small pixel pitches of sensors these days, the CoC from ANY sensor is appreciably smaller than what my CoC needs to be that it no longer matters. When you need a CoC that is at least 50x larger than what you get from the 1D X, it doesn't matter if you photograph something with the 1D X, 5D III, 7D, 7D II, or anything else...its already far smaller than you need it to be for the vast majority of circumstances. Most of my work goes online. Even scaled to "HD" image dimensions, the necessary CoC is 20-30x larger than any sensor today is already producing. Even if I enlarge my photos by 3x, maybe even 4x, to print at 32x48 or 40x60...I'm not going to be standing within a foot to view them. I'll be standing back ten, fifteen, twenty feet, so the increase in distance is effectively the same as NOT enlarging the photos in the first place. My required CoC then is still large enough that 4µm, 5µm, even 7µm pixels are going to resolve more detail than I really truly need unless I am cropping out the middle 10%.
CoC (in that context) has nothing to do with pixels (unless you are extremely picky and good sighted). It is your tolerance for what you accept. My point was that the 1.6x factor stays, regardless of what your tolerance is. It goes back to what you said earlier, and you are changing the topic now.
So yes, there is a difference between FF and APS-C DOF. Its just that the difference doesn't matter in the real world in the vast majority of reach-limited cases...and even when it does...no one actually notices. The DOF benefit of FF shows up when you have the ability to frame identically, but in those cases it is either the focal length or the subject distance that changes by the crop factor, and that, not the physical size of the sensor itself, that changes the depth of field.
I said repeatedly that the difference is for those who care, and most people would be happy with either format. But you are downplaying the benefits again and distorting them. What prevents you from framing identically, how does the sensor size changes the distance to the subject, etc. Stop lying to yourself. A larger sensor alone does not automatically mean the ability to get shallower DOF but the FF system built by Canon does have much greater potential for that than the Canon crop system.
I will stop here because I do not see anything coherent in your posts. You are jumping from topic from topic, each time forgetting what you wrote before and what I replied to.
I'm not downplaying any benefits. You claim that the simple act of cropping
(which is all a crop sensor does) changes the depth of field. If you hypothetically had both FF and APS-C sensors with the same pixel pitch, and you cropped the FF image in post to match the APS-C image, would that change the DOF? Of course not. The two images would be identical.
Pixel pitch puts a lower limit on CoC, which is why I bring it up (and I mentioned this in a previous response, so apparently neither of us can either read nor remember what we've read). A 5µm pixel would limit your CoC to 0.01mm. If you only need a 0.5mm CoC (and I'm being EXTREMELY generous here) for a 2x reduction for publication on the web, then it doesn't matter if you are using a 6 micron pixel, a 5 micron pixel, or a 4 micron pixel. All three would produce results similar enough that no human being could tell any difference for your reduction. You could even enlarge by a factor of two, and still have more than enough "CoC headroom" that the differences in pixel pitch wouldn't matter enough to produce an appreciable difference in DoF that anyone would notice it. A cropped FF with 6µm pixels is going to be perceived the same as an APS-C with 4µm pixels.
Mathematically, purely theoretically, you are correct. A 0.12mm CoC (6µm pixel) will produce a different DoF than a 0.08mm CoC (4µm pixel). I'm not solely trying to debate the simple mathematics of the issue. I am trying to point out that the difference between 0.12mm and 0.08mm CoC has no real-world relevance such that, assuming a focal length limited scenario where an FF and APS-C are used to photograph the same subject, with the same lens, at the same distance, cropping the FF image to match the APS-C image,
DOF would be perceptually
different. I'm arguing the point that DOF has nothing to do with crop factor
, and everything to do with the lens
and subject distance
. That means you can get closer with the FF, or swap to a longer lens, to frame it the same
as the APS-C...and the change in focal length or subject distance is what actually changes the depth of field (and does so in such a way as to give FF a significant DOF advantage over APS-C, yes!
) I am not denying anything, and my argument has been coherent and consistent...I am denying the notion that crop factor in and of itself has any impact on DoF.