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Canon 500mm mk1 f4 focus hunt (1 Viewer)

falconer2406

Well-known member
Hi all, seem to have an issue with my mk1 500mm prime in as much as it doesn't want to lock into focus.
No matter what I try and what setting I use the lens simply won't lock on.
It sounds like a hammer drill in use where it's constantly trying to lock focus on.
I last used this back in June with no problems at all so I'm stumped as to what can be the problem.
I'm using it with a 7d mk2 which works fine when I put the 100-400mm on so I don't think it's a camera issue.
I've cleaned the contacts and tried various settings but no joy.
Anyone any ideas please?
 
What are you trying to focus on? Is it moving? Is your IS on?

Try turning off your IS and if the problem goes away (I suspect it might) then the problem is with the stabiliser rather than the AF. Unfortunately I think IS is more expensive to repair than AF.
 
What are you trying to focus on? Is it moving? Is your IS on?

Try turning off your IS and if the problem goes away (I suspect it might) then the problem is with the stabiliser rather than the AF. Unfortunately I think IS is more expensive to repair than AF.
Firstly thanks for replying.
Unfortunately it doesn't make any difference with IS on or off. I've tried again changing every setting I can think of but the lens still repeatedly knocks, it focus then jumps out of focus on then focuses again then jumps out again and just repeats this process, never locking on.
 
Oh dear sounds like it might be a visit to Canon!

At least you are not too far from Elstree.

Or try Colchester Cameras - they are Canon a certified repair/service center.
 
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