Canon 20D Focussing Issues - DPChallenge Forums

Canon EF 24-105mm f/4.0L IS

08/09/2006 09:50:35 AM · #1

My 20D has been playing up. For some reason, it wants to refocus before taking a shot - focus lock has stopped working. Same for all lenses. It sometimes also locks the trigger mechanism, preventing me from taking any pictures.

I have tried the obvious things, resetting the camera to its factory settings, fiddling with the custom functions for autofocus, reflashing the firmware to the latest version. Nothing seems to fix it.

Does anyone have any more bright ideas?

Thanks!

pmichaud

Canon EOS-5D Mark IV

08/09/2006 09:57:45 AM · #2

Wow! The exact same thing just happened with my 300d. Any ideas anyone? The camera does work in manual focus mode.

kirbic

Canon EOS R5

Canon RF 24-70mm f/2.8 L IS

08/09/2006 10:11:47 AM · #3

Couple questions:
- Does it ever work, or will it *never* lock focus on half-press
- On full press of the shutter button, does the camera AF and lock focus correctly, at least sometimes?

Manic

DJI Mini 3 Pro

Kamlan 28mm F1.4 MF for APS-C

08/09/2006 10:12:20 AM · #4

I presume you've tried this out in all three AF modes (single, ai focus, and ai servo) and made sure the AF-lock button isn't jammed or somesuch?

Nikon AF Nikkor 50mm f/1.8D

08/09/2006 10:24:14 AM · #5

Originally posted by kirbic:

Couple questions:
- Does it ever work, or will it *never* lock focus on half-press
- On full press of the shutter button, does the camera AF and lock focus correctly, at least sometimes?

It will focus, and it will focus lock while I am recomposing, but when I depress the shutter release the rest of the way it will not shoot until it has refocussed on the recomposed frame. When it has obtained a new focus, it shoots.

Originally posted by Manic:

I presume you've tried this out in all three AF modes (single, ai focus, and ai servo) and made sure the AF-lock button isn't jammed or somesuch?

Many times...

deapee

Kodak V803

08/09/2006 10:50:52 AM · #6

20d:

if you're shooting in AF-S mode...then something is definately wrong with the camera or you're letting your finger up somehow when recomposing.

If you're shooting in AF-C mode, once you're happy with the focus, you gotta hit the AF/AE LOCK button to lock the focus...then recompose, but you gotta make sure that in your settings for the AF/AE LOCK button, that you have selected it to lock AF or lock AF AND AE and not just AE. Hope that helps, that's the only things I can think of.

--

300d:

For this one, it's going to be much more complicated...I think the camera can decide what focus mode to use for you so you never know where you're at. If you're in sports mode, I'm pretty sure it's in AF-C though, maybe that'll help you.

kirbic

Canon EOS R5

Canon RF 24-70mm f/2.8 L IS

08/09/2006 10:59:43 AM · #7

If you've addressed the questions that deepea raises and still have the symptoms then it is possible that a switch problem is causing the behavior. It's possible that your switch momemtarily releases the half-press state while being actuated from the half-press to full-press positions. That would cause it to try to reacquire focus.
If you have a remote switch, try plugging that in and seeing if the camera works normally using the remote. If it does, the problem is with the main shutter button switch and/or associated electronics. If it does not, look back again at software settings.

08/09/2006 12:42:21 PM · #8

Originally posted by kirbic:

If you have a remote switch, try plugging that in and seeing if the camera works normally using the remote.

Excellent thinking! Thanks - I will try this.

Canon EF 24-70mm f/2.8L USM

08/09/2006 12:43:34 PM · #9

Originally posted by deapee:

Thanks - I think that it is a camera fault, as I have tried all these settings, but will have another look as you suggest.

Telehubbie

Canon EOS-40D

08/09/2006 12:57:24 PM · #10

Just a thought that you probably checked already, so forgive me if I sound redunantly basic, but is one of your outer autofocus points selected?

PhantomEWO

Canon EF 70-200mm f/2.8L IS USM

08/09/2006 12:57:41 PM · #11

canon will not admit it has this problem BUT it does. My 20D had it, my son's 20D had it and two other people that I know had same issue. All sent back to Canon all came back fixed. Amazing how a non-problem gets fixed so easily at the factory. Just make sure you are on single and not any other focus function. Also set only one of the focus points in the view finder. You probably need to send it back to Canon. Sorry and good luck.