Quote Originally Posted by HDNitehawk View Post
I thought the top three were adequate and fairly equal. I faulted the bottom and it turned out to be the 1Dx III. It may have been the high ISO, but the eye wasn't as crisp as the other three.
I wish I had a better comparison to remove ISO as a factor. This is an ISO 5000 image, so a bit better.

AC8I5506 by kayaker72, on Flickr

Scrolling through the images I kept, It looks like I mostly used the 1DX III with the 1.4x TC and when using w/o the TC, I was at higher ISOs.

As I mentioned, I can see a difference in detail that is resolved. If just thinking about it in terms of MP, I think it isn't much of a difference and attribute much of the issues with the 1DX III image to ISO 8000. But, when looking at it in terms of pixels on target, my bird feeder is ~30 ft from my window. Using the 500 mm lens, that would mean the 1DX III is resolving the birds at my feeder at 211 pixels per inch, 5DIV at 259 ppi, R5 at 316 ppi, and the M6II at 429 ppi. Use a 600 mm lens, and the 1DX III is putting almost the same pixels on target at the 5DIV. Use a 500 + 1.4x TC and you are right at 300 ppi.

At least in my opinion, all of this matters. Resolution is part of the equation, but only part of the equation.