Can't set f-stop on 20D

jboyd wrote in post #2382477
Thanks Liza - did that. It didn't change anything. I then tried my last resort and "reset all camera functions." That worked. I don't know what I possibly could have set that would have not allowed me to set the aperature. I think I will still call Canon support tomorrow.

Thanks everyone for your help!

Jackie

Try taking out both batteries for 5 min.

I have had this problem in the past and it turned out to be bad contacts on the camera. It was intermitent, then all the time. It was a 1 day fix from the local camera shop and the camera hasn't had the problem since.

I'm inclined to agree wioth Basroil, sort of. It sounds like the contact points for the camera (not the lens) are dirty or possibly damaged.

Deductive logic here... two lenses are having problems when mounted to a specific camera. (Aperture reading 00 for your 85mm AND 4.0 for your other lens).

Have you tried putting the same lenses on your 10D to see what happens?

basroil wrote in post #2383045
this looks like a simple case of broken/dirty lens, OR, if all lenses do that, a simple case of i was too lazy to turn off the camera while changing lenses. if it's just the 85 that does it (which you can check with your second body, the 10d), then it's the lens that needs fixing, else, most likely some small firmware glitch that can probably be fixed simply by re-installing the firmware

I'll have to disagree RE lazyness. I've never turned off my camera through possibly a thousand lens changes and have never had a problem. If this could cause a problem, the manual would have mentioned it somewhere, which it doesn't. The lens contacts are set at different heights most likely to allow lens changes when the camera is on.

Sometimes software or settings get corrupted in memory and this is probably what happened as the OP mentioned that once he reset the camera it went back to working normally.

I did use the 10D to finish my shoot and the lenses worked fine on that. Like Steve said, after I reset all camera settings it worked fine. I still need to check the manual to see if setting the focus point to the back wheel inactivated the setting of aperature. But, I doubt it since I have had the camera set that way before and didn't notice any issues before. My day job is taking up too much of my time right now - hopefully I will get to it tomorrow!

Jackie

basroil wrote in post #2383045
this looks like a simple case of broken/dirty lens, OR, if all lenses do that, a simple case of i was too lazy to turn off the camera while changing lenses. if it's just the 85 that does it (which you can check with your second body, the 10d), then it's the lens that needs fixing, else, most likely some small firmware glitch that can probably be fixed simply by re-installing the firmware

I've spoken to Canon reps about turning off the camera to change lenses. They specifically state that it's not necessary.

Jon wrote in post #2389767
I've spoken to Canon reps about turning off the camera to change lenses. They specifically state that it's not necessary.

and, I had the camera off while changing the lenses. I don't open any doors or take off any lenses when the camera is on.