Canon 5D IV Firmware defective???

Jan 17, 2022
Since upgrading the firmware on five of my 5D IV bodies it's impossible to get a crisp tack focus image. It doesn't matter if it's on autofocus or manual.
Best I can get is around 80%. It's worse on my 70-200mm lenses than 50mm.
Anything far away is completely unusable now....
Has anyone else experienced this? I feel like it's semi blurry just looking through the viewfinder.
I didn't experience any of this prior to upgrading.
Has anyone else upgraded to the last couple of firmware's and had focus issues?

Del Paso

M3 Singlestroke
CR Pro
Aug 9, 2018
I've downloaded every available firmware to my 5D IV and haven't experienced a single issue...
Focus (AF & manual) is perfect as usual, no matter which lens I use.


CR Pro
Mar 22, 2012
I assume you didn't adjust the diopter.
I've very bad for doing any Firmware updates - if its not broke etc.
It would seem strange the software would have any impact on manual focus.
Have you tried autofocus manual adjustment?