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20D Focus lock problems

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Tony Rorke

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I have noticed my camera does not always lock focus when I reframe my pictures (even though I keep the shutter button half way depressed and my AF setting is on "single shot"). I am not sure if there is some software setting that I can change to fix this or if it is a hardware problem that needs me to send the camera back to Canon for repair. I have installed firmware version 2.0.2 to see if the problem would go away, but no luck. Has anyone else experienced this problem?
 
You meant "One Shot"? So you half-press the shutter release button on the subject, keep the button half-pressed, then move the camera to recompose the scene? What exactly happens when you recompose?

-Yohan
Tony Rorke said:
I have noticed my camera does not always lock focus when I reframe
my pictures (even though I keep the shutter button half way
depressed and my AF setting is on "single shot"). I am not sure if
there is some software setting that I can change to fix this or if
it is a hardware problem that needs me to send the camera back to
Canon for repair. I have installed firmware version 2.0.2 to see
if the problem would go away, but no luck. Has anyone else
experienced this problem?
Click to expand...
 
When I recompose and then continue to take the shot, the camera refocuses on the new position of the focus point and does not keep the original focus. I dont release the shutter when recomposing, so I dont think this should happen. I also notice that the AE doesnt lock either. Do you think its a hardware problem?
 
I always try to rule out user error before declaring faulty hardware, especially with new forum members, so please don't take my line of questioning as malicious. I'm just trying to help you get to the bottom of this problem.

So you're saying that with the shutter button kept half-pressed, when you move the camera the AF reactivates instead of staying locked? How do you know that this is happening? Is it because your previous subject is now out of focus or do you actually see the lens adjusting focus to a new target?

As an aside, what lens are you using? Maybe you are using a lens with Full Time Manual focus (FTM) and are accidentally moving the focus ring when you recompose?

Also, is this a new camera? Have you changed any of the Custom Functions (C.Fn)?

-Yohan
Tony Rorke said:
When I recompose and then continue to take the shot, the camera
refocuses on the new position of the focus point and does not keep
the original focus. I dont release the shutter when recomposing,
so I dont think this should happen. I also notice that the AE
doesnt lock either. Do you think its a hardware problem?
Click to expand...
 
I need help, so I am very greatful for your line of questioning. I know the camera refocuses, because I can hear the lens motor refocussing and can see it change focus in the viewfinder. Also when I look at the pictures that are affected on my PC, the focus is on the new focus point. Incidentally, I have set the camera so that only the centre focus point is active. I have tested for this problem using the widest aperture (4 to 5) to make sure I am not imagining it. I have a Sigma lens (DC 18 - 125 mm) that is compatible with the 20D. My camera and lens are about 4 months old, but I have only noticed this focus lock problem recently. The only functions I changed were for increasing the ISO range to H (3200) and that was when I first got the camera.
 
The AF mode selection is active only in the Creative modes (P, Av, Tv, M, A-DEP). If you are shooting in Sports (running man icon) the AF mode is AI-Servo. In Green Box it is AI Focus
 
I'm out of ideas except for Lemming51's suggestions below. Look at his/her post and see if that's it. It very well could be. I only ever shoot in Av or M modes, so the shooting mode didn't even occur to me, but it's a very good guess.

-Yohan
 
"Nao was to wait another thing of a so weak DSLR lololol was this that voces was the wait? lolool Great Excrement"

Sounds like the poster and camera are being dissed, though. Care to clarify?

--
...Bob, NYC
http://www.pbase.com/btullis

 
Tony Rorke said:
I have noticed my camera does not always lock focus when I reframe
my pictures (even though I keep the shutter button half way
depressed and my AF setting is on "single shot"). I am not sure if
there is some software setting that I can change to fix this or if
it is a hardware problem that needs me to send the camera back to
Canon for repair. I have installed firmware version 2.0.2 to see
if the problem would go away, but no luck. Has anyone else
experienced this problem?
Click to expand...
Check your custom function settings for AF/AE lock (CF4, I think). Make sure it's set to "AF Lock/AE Lock" which I think is CF4=0.
 
I use the Av and P settings most often and have the problem on both. I have also checked that my custom function 04 is set to 0. Problem still persists. I remember first becoming aware of this problem when I changed my AF setting from 'one shot' to 'AI focus' for some photos and when I changed back to 'one shot' the camera would not focus lock. Incidentally, I really love my 20D. I have managed to get some fantastic photos with it! If I could just fix this problem without having to send it back to the dealers, I would be very happy.
 
As subject - this will put AF lock onto the * button, with AE lock only on the shutter button.

This will rule out shutter button problems.

--
Tony Collins
[email protected]
 
I am amazed. I just have to get used to pressing the * button now to focus....but it works!!! The focus lock works now and the AE lock too. Thanks very much.
 
Can't say that I experienced the same thing that you did, but I have been using that custom function dating back to my first Canon AF camera.

It can also be very useful for Servo AF mode. Once you get used to it, its awesome!

I think focusing on the intended subject with the center point and recomposing is much better than changing the AF point every time. Plus, for certain panning situation, you still have the freedom to change AF points if desired...

jt
--
Lots of Cameras, lots of lenses, not enough time...
 
Tony Rorke said:
I am amazed. I just have to get used to pressing the * button now
to focus....but it works!!! The focus lock works now and the AE
lock too. Thanks very much.
Click to expand...
I also have been using this function for a long time now. Two "problems" I have found is inadvertently pressing the button to the right and wondering why it doesn't focus lock! And secondly, having to remember to half press the shutter button to turn on the camera. But, all in all, its a good function and once mastered, you won't go back to the default CF4.

Cheers
Sheila

Sheila Smart
Sydney, Australia
http://www.pbase.com/sheila

All the technique in the world doesn't compensate for the inability to notice - Elliott Erwitt
 
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