topic Re: Extreme Slow AF after zooming in EF70-200 2.4 MKII in EF & RF Lenses

Extreme Slow AF after zooming in EF70-200 2.4 MKII

MacMooten — Sat, 12 Apr 2025 16:56:49 GMT

Okay….i have a R6 (mk1) and shot several rugbymatches without any problems. Crystal sharp using the R6 with a converter ring + extender 2x (mkII) + a EF70-200 2.4 MKII. And as mentioned. Perfectly sharp pictures and quick focussing.

But now…all is sharp….no problem. Players at different distances are in focussed perfectly. And the autofocus has not a problem shifting between the subjects. BUT…..when I zoom in completely the camera won’t focus on the subject. The image is a bit hazy…and after some movement it slowly seems to get into focus. After that….the players can run as fast as they want. Towards me, away from me….autofocus is ‘perfect’ (okay….the lens sometimes can’t keep up. But that’s all within acceptable margins). As long as I keep it in that focal length all works perfectly. Zooming back….auto focus works perfectly. Even zooming out with continue AF works as one might expect. But again….when I turn the zoom fully open….again it seems to need a lot of time….a LOT of time to find some focus. The focus indicator behaves like all is locked in focus but the image is hazy….until some movement with the camera and yes…there it is. It seems like this problem only occurs when the zoom is used at its full. Zooming in just one small step before the ring can’t get any further seems to no problem. The problem occurs typically after zooming completely in.

Used another lens….no problem with AF. Tried to skip the extender (of course) and the problem with the 70-200 still occurs with the same behaviour. Also did a body reset. No difference.

Could this be the end of my beloved 70-200…just out of nothing

Re: Extreme Slow AF after zooming in EF70-200 2.4 MKII

deebatman316 — Sat, 12 Apr 2025 18:04:27 GMT

Does the lens work properly with the extender removed. Also which model teleconverter are you using. Note it’s normal for the AF to slow down when a teleconverter is mounted. The manual highlights this information.

Re: Extreme Slow AF after zooming in EF70-200 2.4 MKII

MacMooten — Sat, 12 Apr 2025 19:11:59 GMT

Yes….the problem exists with and without the extender. That being said….no problem occured two weeks ago. Both with extender or without the extender worked perfectly an at a very good speed 😉

Re: Extreme Slow AF after zooming in EF70-200 2.4 MKII

deebatman316 — Sat, 12 Apr 2025 19:31:29 GMT

Have you tried the lens on a different camera instead.

Re: Extreme Slow AF after zooming in EF70-200 2.4 MKII

shadowsports — Sat, 12 Apr 2025 19:42:25 GMT

Greetings,

Its very possible the lens has become tired or is out of calibration.

Do make sure you have Lens Drive When AF Imposible > Enabled.

To my knowledge, Canon is still servicing the EF 70-200 f2.8 mkII. You can have an inspection / maintenance service performed, or consider an RF equivalent. However, you'll have to buy the Z if you want to use it with an extender.

Re: Extreme Slow AF after zooming in EF70-200 2.4 MKII

MacMooten — Sat, 12 Apr 2025 22:28:26 GMT

With your answer in mind. Could it be that (bearing in mind that the lens is a ‘senior’ one) it had enough of me walking with the camera turned on between the game halfs or sometimes between two games with the autofocus still on. I felt it ‘moving’ in my hands constantly and (okay….call me stupid) never thought that that would harm this lens (or maybe every lens)

yep i can only assume what the answer will be and man how stupid I feel.

Re: Extreme Slow AF after zooming in EF70-200 2.4 MKII

ebiggs1 — Sun, 13 Apr 2025 16:22:23 GMT

"Crystal sharp using the R6 with a converter ring + extender 2x (mkII) + a EF70-200 ~~2.4~~ 2.8 MKII."

The solution is quite simple, try the lens on a camera it was designed for like a 5D Mk III, etc. And do it without any adapters or extenders. Same result or still worried something is amiss send it to Canon for a C&C. You might check to make sure they still service that lens first. But you probably need to do it sooner than later anyway. Otherwise you need to find a private shop that works on Canon lenses.

If you don't you will always wonder!