What does Error99 mean?

First time ever this weekend I got this Error99 message on my camera.

I was shooting Macro with my 20D, Grip, 100mm Macro, and RingFlash and went vertical on my monopod and got this error.

Anyone have an idea what my camera is trying to tell me? I just turned the camera off then on again and it went away.

Thanks.

What does the manual say?

Uusally error between lens and body. Hard reboot camera (remove battery) after removing and remounting the lens. Maybe try an eraser on the contacts.

Err99 is a catch-all. In your particular case it might have been that the extra weight of the ring-light on the macro lens caused the lens and body electronic contacts to pull slightly apart. Why in Portrait orientation? Because ofthe angle of the stress. Options? IIRC someone makes a mount whiich will support both lens and body for just these shotting situations.

Jon wrote in post #2352451
Err99 is a catch-all. In your particular case it might have been that the extra weight of the ring-light on the macro lens caused the lens and body electronic contacts to pull slightly apart. Why in Portrait orientation? Because ofthe angle of the stress. Options? IIRC someone makes a mount whiich will support both lens and body for just these shotting situations.

Another very viable problem causing the error. SL, Process of elimination will find it for you.

Just means some cosmic wind was blowing the right direction to throw some crazy space energy into your camera and make it go crazy.

according to this blog, he called Canon service and was told to clean the lens contact surfaces. My understanding has been that it means a body/lens is having communication issues, but I don't recall an official note from Canon about this.
http://www.richardsnot​es.org …50mm-lens-contact-points/

Err99 is a general error which may mean the body and lens are experiencing communicatiooon issues. It has also occurred for shutter problems among other causes. It's a general "Something happened that we didn't expect; we know something's wrong but aren't sure quite where".

Oh boy, my favorite subject. (just kidding). Anyway, it sounds as if you have a transient ERR99 and maybe the flash hanging off was the cause. Keep an eye out and see if it comes back. Anyway, sometimes cleaning the contacts works if the cause is poor or intermittent connections. But it can also be something worse. I had two lenses one which would not focus and would ERR-99 and the other constantly overexposed because it could not adjust the aperture. That also ERR-99ed. I would keep an eye on your picture quality as well and keep an eye out for other symptoms which could indicate an imminent mechanical failure as well.

It's like a check engine light, but worse.

Err99 on my XT (and I presume it's similar on other models) is pretty meaningless.

On my XT I get this with my Tamron 70-300. It's not a dislike of the lens nor dirty contacts. It seems purely random. I shot 150 photos with that lens on without removing it. At about shot 100 the camera locked up with err99. I powered down and up and carried on for another 50 shots before removing the lens. I am beginning to suspect it's something to do with light levels.

I took some photos of the moon last night with the Bigma and thought something was strange when the image on the lcd screen after I took the shot appeared sooo blurry---nothing like I was seeing in the viewfinder.

I went inside and tried turning off the XT. It wouldn't turn off and pretty soon err99 started blinking. I took the batteries out and put them back in. I also took the lens off and put it back on.

I went back outside to try shooting the moon again and now I was getting much sharper images. The manual mentions that it sometimes is caused by using non-Canon lenses. This is the first time I've gotten the err99 in almost 2 years of use.

Ya same here, its been about 1.5 years since I got my 20D... never got an err99 till now. Hopefully I dont see any more of it, not very comforting.

rhys wrote in post #2352722
Err99 on my XT (and I presume it's similar on other models) is pretty meaningless. ...

Well, meaningless is not quite the right term. It means a lot, it's just that it means so much that one can not simply diagnose what it means. It can be something as simple as the lens not making good electrical contact, or it can mean you have a serious mechanical failure with the aperture mechanism, or it can mean that there is some electrical problem in the body of the camera.

I had 4 separate ERR99 causes on my then brand new XT. It took 3 months working with Canon service to fix them all. It also took some intuiting, that is looking for some other symptom such as one lens started over exposing shots getting more and more overexposed, then it eventually ERR-99ed. Removing the lens and jiggling it solved the issue. When Canon got this info, they were able to replace the mechanism and I have not had a ERR-99 on that lens in since.