R5 mk1 no longer focusing at infinity with EF lenses at wide end

[polaris8030]

A recent issue with my camera has me stumped 

Body: R5 mk1 + EF adapter 

Issue seen with EF 16-35 F4L mk3, EF 24-70 f2.8L mk2 and 100-400 f4.5-5.6L mk2

At the wider zoom end of these lenses I cannot get the camera to focus at distant objects. Only by increasing zoom I can get focus.

16-35 .. distant focus  when zoom > 20

24-70 .. zoom > 50

100-400 .. zoom > 150

Auto or manual focus .. same result

Not related to shutter speed or aperture 

Controlled subject, lighting, use of tripod etc 

I have a 5DSR as well and the issue is not seen with any of the above lenses, again using auto and manual focusing. 

This makes me think that the problem is with the body and adapter and not the lens. 

Problem appeared out of the blue. I use my gear about once every two weeks.

Thanks

[deebatman316]

Are you using the Canon brand mount adapter. 3rd Party Mount adapters are nothing but trouble. Also are you sure you have the EF 16-35mm F/4L IS USM III lens. Canon hasn’t released such a lens. They’ve only made 1 version of the 16-35mm F/4 lens. However they’ve made 3 different versions of the F/2.8 model. You should be able to manually focus to infinity. The focus rings are all mechanically connected to the lens’ focusing elements. None of these lenses are focus by wire.

[polaris8030]

Hi @deebatman316, valid questions - I use a Canon adapter and my bad about the 16-35, it's a f/2.8L lens

Here's another way to explain what I am seeing through the viewfinder. If MF focus aid is enabled, then there are 3 white triangles that show up in the viewfinder. When focus is achieved the triangles merge into two (top and bottom align vertically and color changes to green). With all my lenses, if zoom is at the widest, the triangles do not converge. Again, no problem focusing at the widest zoom with my 5DSR with any lens. I believe this rules out the lens(es) as the issue.

I will be calling Canon on Monday. Hopefully its not some expensive repair related to the sensor. This problem just appeared recently and out of the blue. No misuse of the body, lens etc. or anything else that I can think of. Just strange. Thankfully I had a backup body (5dsr) and the r5 was still usable, just not at the widest zoom.

ps - I also did a camera reset. Did not fix.

[Waddizzle]

How far away is the subject?

What AF mode are you using?  Servo or One Shot?

Do you have the same focusing issue when the camera is shooting mode is set to the factory default, Intelligent Auto?  That’s the Green [A+] setting.

[polaris8030]

How far away is the subject? Right now my test is on houses across the street, ~100ft and further

What AF mode are you using?  Servo or One Shot? Tried with both, does not make a difference. Also, I have used manual focus as written above.

Do you have the same focusing issue when the camera is shooting mode is set to the factory default, Intelligent Auto?  Yes, reset camera (basic settings) and tried with A+, P modes - no change to issue.

So, later today I did a swap test with a friend's R5 and EF lenses. My EF lenses worked fine on his body and I had the same issue with his 35mm f2, a 70-200 f2.8 but interestingly no issue with his 400mm f2.8 and a 600mm f4 (all EF lenses). We also made sure to swap test the adapters and the issue followed my R5 body.

At this point, its a call to Canon and work it out from there. 

[polaris8030]

thought I'd give an update to this thread. Here is the diagnosis from Canon repair "A technician has evaluated your product and determined that the flange back is out of standard. Unit needs open repair to make adjustments and correct CMOS and mount distance"

Cost will be a bit shy of $400 - which is what it is - but I was honestly expecting worse (like something wrong with the sensor)

How could the flange back get out of spec I wonder. It does make sense though that the problem is with the body and not the adapter since that's what my swap tests were showing. 

Well, I hope its not a sign of a deeper problem with my body and maybe such things happen with use. My body is ~4 yrs old now.

[Waddizzle]

That is a little odd.  How often do you remove the mount adapter?  I never remove, not unless I am using an RF lens. 

[LeeP]

Do you use RF lenses on your R5? If so do they not function properly? This is a most fascinating development. I have nearly transitioned my to RF, but I still have several lenses that are EF that I will not waste money transitioning over. 

[polaris8030]

Like never. Only time I might have removed the adapter is to send the sensor for cleaning.

I don't know what to make of this diagnosis. Trying to think what kind of forces can displace the flange back but not cause the rest of the body to be impacted. Can't come up with anything. Maybe its a wear and tear thing - honestly don't know.

[polaris8030]

I have zero RF lenses, all EF. Same reason - the EF lenses work beautifully, and I hope they continue to do so.

Apparently the adapter got a clean bill of health, since I sent both body and adapter for repair.