nat Loc: Martha's Vineyard, MA

The AV mode on my 7d appears to be gone. Shows up as 00 no matter what. Canon help is closed for the weekend, of course. I'm wondering if it is the camera or if maybe I hit a wrong setting. Have been shooting for an hour or so, and it suddently disappeared. Thanks in advance.

Copeman

Seems unlikely, but have you turned camera off and removed battery?

St3v3M Loc: 35,000 feet

I don't see 00 in the list http://www.learn.usa.canon.com/resources/articles/2012/eos_error_msgs.shtml
And assume all the other modes work...

Have you tried removing the lens and replacing it?Have you tried removing the battery and replacing it? Have you tried a factory reset?

Keep us informed. S-

marki3rd Loc: Columbus, Indiana

Are you saying that when you set the main selector knob on the top of the camera to "AV" position the aperture reads as "0"? Sounds like a communications between the lens and camera body electronics problem to me. I would start with the suggestions made by St3v3M above. I hope you can solve the problem.

amfoto1 Loc: San Jose, Calif. USA

When I have seen that happen on various cameras... it usually was because the lens wasn't fully rotated and locked in place. The camera shows "00" because the contacts and pins aren't aligned and making connections, so the camera doesn't think a lens is mounted. Sometimes this happens when switching lenses. Other times it can happen by accidentally bumping the lens release button at the same time you're turning the focus ring or zoom ring.

Pretty easy to check.... and important! Be careful... if not fully latched, it's also all-too-easy for the lens to fall off and get damaged!

If that's NOT the case with yours, you might try removing the lens and cleaning the gold lens to camera electronic contacts. Maybe something is blocking communication between the camera and lens. Try cleaning those contacts with a clean, lint free rag that's been lightly moistened with isopropyl (rubbing) alcohol. That will remove any oils or grease, which is usually what's causing the problems. (Don't use a pencil eraser... which is often recommended. Those are made from vegetable oil and won't remove any sort of oily substance.) Also check the corresponding "pins" just inside the front of the camera, that none of them are "stuck". Those are spring-loaded to insure good contact with the lens. A little light pressure on them should show some movement, but they should pop fully back out in place when release. Be careful not to touch the mirror or anything else while inspecting those pins.

Other than that.... if the mode dial is correctly set to Av, the lens is fully rotated and locked in place, and those contacts are clean... it's probably a fault with the camera or lens. Most likely would be a broken flex cable inside the lens. I'd expect that or a failed aperture mechanism would cause an ERR code. Still, try a different lens on the camera and see if it works properly. If so, you know the fault is with the first lens. If not, if neither lens' aperture can be controlled and "00" is shown with both, then it's some problem with the camera's aperture controlling circuitry (pretty unlikely).

Yes, turning the camera off and back on, or removing the battery and replacing it, doing a reset or even re-flashing the firmware all might correct a software-related glitch. Those are all easy to try yourself, but frankly are rather long shots to correct anything.

LoneRangeFinder Loc: Left field

Not a Canon user, so feel free to totally ignore my advice. Try a camera re-set.

boberic Loc: Quiet Corner, Connecticut. Ex long Islander

Along with the battery removal, clear and format the card, then remove it. remove the lens. Then re-install the battery, another lens, a new card. Be sure to turn the camera off when removing the battery. Switch the dial to another setting and then go back to AV. Turn the camera on. If none of that works--you have a perfect reason to upgrade to the mk2 version.

marki3rd Loc: Columbus, Indiana

srodday Loc: Mass

Removing and replacing the lens worked for me when it happened.

Is everything working now?

ronz Loc: Florida

You should have a place in your menu to "reset to defaults". You may try this after removing the battery and see if that works. If not try the reset.

Toment Loc: FL, IL

Had to return my G12 because that mode wheel malfunctioned. Repaired w/o problem by Canon. Charged me minimal amount, G12 was out of warranty.

mwsilvers Loc: Central New Jersey

It a communication with the lens issue. Make sure the lens is fully locked into place. Check the other modes besides Av. If its 00 in AV it should be that way in the other modes as well.

mwsilvers Loc: Central New Jersey

That's great, but what does that have to do with the OP's problem with his 7D?

cambriaman Loc: Central CA Coast

Try all the above and then if all else fails, learn to shoot Manually.

mwsilvers Loc: Central New Jersey

I know you were kidding, but I'll bet if he's getting 00 it won't work in manual mode either even with manual focusing. Although he hasn't followed up, the 00 is likely appearing in the aperture location in the viewfinder. That would be a result of a lens communication issue.