70d af, could someone evaluate?

apersson850 wrote in post #16951754
It doesn't have to be the camera's AF that's at fault. Such a small difference may very well be due to the lens not being perfectly symmetric. Thus at the same distance setting, you get different sharpness across the frame.
Does the focusing ring run to the same setting in all three cases?

I was thinking about lens decentering when I asked the OP to shoot a grass lawn.

apersson850 wrote in post #16951754
It doesn't have to be the camera's AF that's at fault. Such a small difference may very well be due to the lens not being perfectly symmetric. Thus at the same distance setting, you get different sharpness across the frame.
Does the focusing ring run to the same setting in all three cases?

I only hear the beep, 24 105 is quite a silent lens. But with with the 70 300 nonL, I can tell that the focusing ring is running on the same process of shots.

MakisM1 wrote in post #16951930
I was thinking about lens decentering when I asked the OP to shoot a grass lawn.

Ill try some photos of a grass lawn this afternoon... What's lens decentering?

I was referring to if the focusing ring stops at the same distance, as far as one can eyeball it, not if it's running at all.

Lens decentering or assymmetry is when something isn't perfectly aligned along the optical axis in the lens. It can give such effects. If I shoot a plane structure, like a wall, with my EF 24-105 mm f/4L IS USM, for example, then it's not equally sharp all across the wall, because the focus plane isn't perpendicular to the optical axis.
I used to have an EF 28-135 mm f/3.5-5.6 IS USM too, and that was the same, except the focus plane was slanted in the other direction.

That could be what you see. But it doesn't have to be the reason.