Where is “mirror-lock-up” in the EOS R’s menu?

J A C S wrote:

gimp_dad wrote:

J A C S wrote:

gimp_dad wrote:

J A C S wrote:

gimp_dad wrote:

J A C S wrote:

gimp_dad wrote:

J A C S wrote:

shawnphoto wrote:

It is not what is causing the focus issues on the 70-200. If there was noticeable focus shift on a long lens it would be worthless.

Unless it is near MFD only...

It's not focus shift. The vast majority of all the failing tests are focused and shot at the same aperture.

Then how do you know?

Just using the definition I linked above. The accepted definition is specifically about the focus shifting due to different apertures being used to focus vs shoot.

No, this is not what the definition says. "Focusing" in the first sentence refers to the plane (surface) of focus (dependent of the aperture). You cannot test for it unless you change the aperture and you specifically said that the testing so far has been done at a fixed one.

Clearly the focus issue at F2.8 focused and shot at F2.8 is not by definition Focus Shift.

It is not clear at all, see above. It may not be but nothing we know so far says that it is not. First, the camera and the lens may correct poorly. Second, the camera does not always focus wide open. In strong light, it stops down.

Any evidence to support this point with the R and the RF70-200?

The point that this might be the reason?

Either way, most of the shots I've seen exhibiting the problem either here or fredmiranda.com were shot indoors. The most reputable ones taken with a tripod at relatively modest light levels.

Poor compensation?

I see your point. Seems plausible. Hopefully the FW programmability in these modern lenses allows a lot more algorithmic flexibility than the old days and they can avoid or accurately fix that type of issue.

If focus shift exists, then there are two issues. Not really interested in arguing the obvious any further. We may actually find that this lens exhibits Focus Shift, but I don't think it does in any material way since the problem diminishes as the lens gets further stopped down from wide open at all distances and FLs.

This is exactly how focus shift behaves on the EF 50L.

Not surprising. Except it does not exhibit focus shift when focusing and shooting at the same aperture (which is about F2.5).

Actually, it does. I think that it is compensated to focus well wide open and it shows focus shift at f/2.8, which is the aperture used to AF.