300D Autofocus Help - DPChallenge Forums

Canon EF 24-70mm f/2.8L USM

12/24/2006 12:20:13 PM · #1

Has anybody had this problem? My Digital Rebel developed an autofocus issue this morning. The lens seems to focus just fine in AF mode, but the green focused indicator in the viewfinder never comes on, and the camera won't let me take a picture. The red focus dots in the viewfinder sometimes come on briefly but don't stay on. The lenses seem to twitch a little trying to find perfect focus. I need to switch the lenses to MF to take a picture. This problem is occurring on all of my lenses, so I think it is a camera problem, not a lens problem.

This is usually how it acts when the light is low and the camera can't focus, but I was shooting outdoors in plenty of light. I tried powering down and back up, changing batteries, changing from AI-servo to one shot but nothing worked.

Am I missing anything? What else should I try?

Thanks!

kyebosh

Canon EOS-20D

Canon EF 80-200mm f/2.8L

12/24/2006 12:31:38 PM · #2

Sounds like a body problem to me. Did you install one of the firmware hacks by any chance? There was a mode in there that would let you focus but not take a picture, but it doesn't sound like that's the problem you're having.

Simms

Canon EOS-5D Mark II

12/24/2006 12:35:23 PM · #3

what mode is AF set to? AI Servo or one shot? If its in AI mode it may be because it is switching into servo mode in which case you will not get a `lock`.. That is probably your first port of call..

As a subnote AI servo is no substitute for Fulltime servo and why Canon left that option out of the 300D is a mystery.. the 300D is a great camera otherwise (especially with the firmware hack).. which will probably lead you onto your next question :-)

Mark

PS, I just reported your post to the admin as I acidentally clicked the report post button instead of the `quote` button... too much xmas wine already I guess. :-) "Hic"..

Originally posted by sailracer_98:

Has anybody had this problem? My Digital Rebel

developed an autofocus issue this morning. The lens seems to focus just fine in AF mode, but the green focused indicator in the viewfinder never comes on, and the camera won't let me take a picture. The red focus dots in the viewfinder sometimes come on briefly but don't stay on. The lenses seem to twitch a little trying to find perfect focus. I need to switch the lenses to MF to take a picture. This problem is occurring on all of my lenses, so I think it is a camera problem, not a lens problem.

This is usually how it acts when the light is low and the camera can't focus, but I was shooting outdoors in plenty of light. I tried powering down and back up, changing batteries, changing from AI-servo to one shot but nothing worked.

Am I missing anything? What else should I try?

Thanks!

Canon EF 24-70mm f/2.8L USM

12/24/2006 12:37:19 PM · #4

That's an idea. I do have a firmware hack on there. I'll see if I can figure out what setting that might be.

Thanks!

Simms

Canon EOS-5D Mark II

12/24/2006 12:38:19 PM · #5

Its ok, Just read your bit about the AI/One shot... ignore me.. laying off the wine for the night now..

Merry Christmas!

12/24/2006 12:39:31 PM · #6

Originally posted by marksimms:

PS, I just reported your post to the admin as I acidentally clicked the report post button instead of the `quote` button... too much xmas wine already I guess. :-) "Hic"..

That's funny- I just about did the same thing to kyebosh, but I caught it just before I hit send/post!

Canon EF 24-105mm f/4.0L IS

12/24/2006 01:05:12 PM · #7

Ok, I've figured it out. The firmware hack focus mode was overriding the normal camera focus mode settings. As a note for others who might run into this, you change this setting by holding the right arrow button and rotating the selector wheel. I must have unintentionally changed this from OS or AI to SE (servo mode?) when I was adjusting the flash exposure compensation the other day.

Thanks for the good suggestions!

Art Roflmao

Canon EOS-6D Mark II

12/24/2006 03:05:34 PM · #8

This is a bizarre coincidence, cuz I ran into the same (or similar) problem on my 300D - won't autofocus for crap - with any lens. Driving me friggin nuts. I have no hacks (maybe I need one?) - I was messing with AEB mode the other day and I think that's when the problem occurred. ANY IDEAS??

Art Roflmao

Canon EOS-6D Mark II

Canon EF 24-105mm f/4.0L IS

12/24/2006 05:33:50 PM · #9

bump because I suck at manual focusing. :( Maybe I should look for the hack...?

Prof_Fate

12/24/2006 05:44:48 PM · #10

try cleaning the camera. could be some dirt or oxidation on the lens/body contacts or a speck of dirt in the mirror box that just happens to be sitting on the AF sensor.