Rebel EOS Auto Focus Problem? Manual Focus Okay

Discussion in 'Canon EOS' started by hugh_d__ft._laud__fl_, Nov 25, 2005.

  1. I have two 18-55 lenses and neither one will auto focus. I have
    never had a problem with either lens until now. Both quit auto
    focusing simultaneously. A new lens is not out of the question but
    prior to purchasing one (a) is the problem in the lens or camera (b)
    is there an ?at home? remedy/test to determine/repair the fault?
    I am aware that the 18-55 (standard equipment) economy/kit lens
    leaves much to be desired but it works well for my eBay listing(s)
    application. The majority of my photos are indoors within 20 feet,
    tripod mounted camera using available natural light? any lens
    Thank You in Advance?
  2. odds would be astronomical that both lenses quit working in the same way at the same time. I would look to the camera. If you have another
    known good canon lens try it and see if you end up with 3 that dont autofocus.
  3. You can easily confirm it by taking your lenses to the nearest Best Buy and asking to test them on the display model. Meantime, try a hard reset of the camera, removing both batteries overnight, and try cleaning the lens contacts on the body gently with an eraser (hold the body so the detritus falls out, not into the camera). Give your battery a full charge. If it still isn't working, then you will need to have it serviced by Canon - hopefully it is still under warranty.
  4. It's probably your camera. Do you have any other lenses to try?

    Not sure what Rebel you're talking about, but if it's the XT, have you set the custom functions that moves AF start to the * button? Or if this is the original Digital Rebel, are you using a firmware hack that allows this?
  5. And just to cover all the bases I can think of right now, are both lenses set to AF & not M ?
  6. Disclaimer, I am providing my findings for informational purposes and should you try this at home, you do it at your own risk. I take no responsibility for what may occur should you try this at home.

    With that said, I have the Canon EOS Digital Rebel that I bought a couple years back and my camera start doing the same thing the past weekend. I was taking pictures out on location in a dim atmosphere and the camera half way through my evening just would not auto focus anymore. I had a Promaster 5750DX flash head installed which has an auto focus assist built into the flash that worked like a charm even in a complete darkness. I discovered the next day evening in bright lighting, that the auto focus will not work, meaning the lens just goes in and out without finding focus.

    The camera still works fine with manual focus and I had tried 2 other lenses and none would auto focus, so I knew it wasn't the lenses.

    I did figure out how to make the camera work with auto focus, however it wasn't much of a solution. Inside the body and just behind the lense is the mirror that moves up and down when you take a picture. However it is a two piece mechanism. There is the top mirror that has the reflective material that you see through the lens with, then there is the part just under the mirror that has something to do with the auto focus. If you manually lift the mirror up and let it slap down (probably not recommended by canon), the lower part should drop down into a vertical position back by the shutter curtain. You'll know when the mirror looks differently and you can see the reflections of the focus points when looking back strait into the camera. If you put the lens back on and turn on the camera, you will find that the auto focus works again. However if you take a picture, the lower part of the mirror will stay in the down position and 85-90% of the picture is blocked by the lower mirror.

    You can lift the mirror back up and flip the back portion back up to the front mirror and the camera will once again take good manual focus pictures, but the auto focus will not work again.

    So what have we learned here? Not much to solve the problem without the need for sending your baby to NJ for service, but I thought it was information that might be good to know to see if your camera will once again auto focus with the above steps that I took. You might be able to drop down the back section of the mirror without letting the mirror slap down, but I found that worked for me. Why it doesn't do this one it's own while taking a picture, but will do it when you gently lift the mirror up to the felt padding and then let go, is beyond me.

    Hope this might be helpful.
  7. Good catch, L Grinstead. There might even be a way for a user to do the repair himself. I'll have to remember this. Thanks.
  8. here's another link regarding someone else's experience with this problem and dealing with Canon.
  9. Hi! It looks like I have the same problem - focusing mirror lifting mechanism doesn't work...

    Is there a way to fix this problem so that both autofocus will function properly and there won't be black parts on the image?
    It's quite expensive here in Belarus to fix that and I'll have to trabel more than 300 km... If only I could find technical descriptions with images on how the focusing mirror lifting mechanism should work and where are located those parts - my dad could fix that, he has enough skills for that (he used to fix TVs and other stuff like this, now he deals with computers).

    I would be enourmosly grateful for any help! Thank you in advance!
  10. Alena, check these links out.
  11. Jim Strutz, thanks a lot! Working on this.
  12. Thought I would add my 2c just in case somebody stumbles across this old thread in the future...
    I recently had an issue with my old Canon 400D no longer Auto-focusing with any lens. I first got err99's immediately after I had trouble removing my nifty fifty (jammed on, used force to remove it cracking the crappy plastic mount). After a while the errors stopped, so did the AF...
    In my case it was the very left pin in the body lens mount (AF pin) had jammed down (possibly slightly bent from using force to remove the 50?)
    What I did was apply a little Isopropyl Alcohol with a cotton tip and worked it up with a sewing needle carefully. After it came up enough to grab it with tweezers I applied more alcohol and worked it carefully up and down until it was springy like the two next to it.
    Have not had an issue since, but am also not using that 50 anymore either...

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