Focus shift - may be more prevalent than I realized

So I read this post by Kickflipkid687

https://photography-on-the.net …p=16638149&post​count=2851

referencing this article

http://www.reikan.co.u​k …focus-shift-reikan-focal/

Now the results for the 70-200 f4 IS rather surprised me. BUT I have been having some 'issues' with some of my lenses whereby I end up MFAing the lens depending on the situation I was shooting in (all close-ish distance). I was thinking maybe the light or something was slightly affecting the focus and MFA.

However, after testing several of my lenses I think focus shift may certainly be a major component of what I was experiencing.

I would say, however, that I was not able to replicate the above result. At about 6ft or less with the 70-200 the DOF is small enough that the focus shift makes a difference. At 30' I can't detect any.

My 135 definitely has some focus shift too - going from f2 to f2.8, then it seems consistent through f5.6. Occasionally I use this lens near the MFD and have noticed I have had to change the MFA as it seemed to back-focus. I thought it my be MFA changing with focus distance, but I not think it is focus shift. At a normal head-and-shoulders portrait distance I don't think it would be noticeable.

Just another discovery made possible by pixel-peeping

FWIW I found the easiest way to test this was to find a subject at an angle (e.g. wall) and simply manually focus on a mark in LV (wide open), then change the aperture and press the DOF preview. In the case of the 70-200 f4 IS and 135 the focus shift after closing down a stop was obvious even with the slight increase in DOF. But as I said, it was only obvious at fairly close distances where the DOF is small enough.

This is an example from the 70-200 f4 IS. Images are 100% crops taken at f4 and then f8 with the focus exactly the same. Subject distance is about 5ft. Difference is subtle, but may corresponds to a +3 to +5 MFA (about that on my 135) which in some cases, with some lenses could be significant.

What camera body is this with?