Sticking Aperture Clears up on its own?

Weird question I guess..

Earlier was shooting with my 100mm f/2.8L IS, everything was going nicely, and then my 7D "locked up" while shooting, refusing to shoot, acting like the buffer was full when the buffer was -not- full... Turned the camera off, then back on and it came back, but then everytime i fired a shot the aperture "hung" a bit after taking the picture, leaving the viewfinder dark for a second or two after the exposure... It also sounded a bit weird "grinding" almost... The camera locked up a second time, i turned it off and then went to do something before going back to it and trying to diagnose it..

When i went back and tried to use it the lens and camera functioned perfectly and i shot another 200-something exposures at a bunch of different aperture settings without repeating the problem

When it was having issues i even went and checked the aperture and the shape went from circular to more oblong than i remember it being, I know that apertures dont usually stay -perfect- but this definitely looked off... I looked again now that its working "right" again and the aperture looks 100% normal...

Should i be concerned or is this possibly just a "fluke" thing...

Depends, if you depend on this lens for a living, then I would send it in right away, if not, meh, just keep using it till the issue becomes more prominent. Thats just me though.

try mashing the dof preview button to see if the aperture freezes up. Use a small f stop to make sure that the blades are closing properly.

musashi wrote in post #14227914
Depends, if you depend on this lens for a living, then I would send it in right away, if not, meh, just keep using it till the issue becomes more prominent. Thats just me though.

Thats what im planning on doing, if it was under warranty id send it off right now, but its not

It is my most used lens, and spring is sorta here so... Yeah... it will suck if it dies in the middle of flower/bug season

Not normal. I'd send it off, especially if it's one you use a lot.

Reading your description, I'm not fully convinced it's the lens' aperture. It could be, but it also could be a problem with the camera instead. Have you tried other lenses and seen the same thing happen? Or, do you have a second body you could use the lens on, to see if the same thing happens?

It is suspicious, if the aperture appears out of round, oblong or oval some of the time. It should appear close to perfectly round. So, I'm not saying this isn't the lens... Just that the described symptoms, other than the out of round aperture, might be in the camera body too.

I agree, a number of tests with the DOF preview button might tell you something. Be sure to try it at various apertures.

Something you might want to try.. Clean the lens-to-camera contacts. just slightly moisten a clean cloth with isopropyl (rubbing) alcohol and carefully wipe the contacts with that.

This is the same thing that happened to my 300. Worked intermittently but then the aperture packed it in.

amfoto1 wrote in post #14229807
Reading your description, I'm not fully convinced it's the lens' aperture. It could be, but it also could be a problem with the camera instead. Have you tried other lenses and seen the same thing happen? Or, do you have a second body you could use the lens on, to see if the same thing happens?

It is suspicious, if the aperture appears out of round, oblong or oval some of the time. It should appear close to perfectly round. So, I'm not saying this isn't the lens... Just that the described symptoms, other than the out of round aperture, might be in the camera body too.

I agree, a number of tests with the DOF preview button might tell you something. Be sure to try it at various apertures.

Something you might want to try.. Clean the lens-to-camera contacts. just slightly moisten a clean cloth with isopropyl (rubbing) alcohol and carefully wipe the contacts with that.

Already cleaned up the contacts and everything, even after it started to work right again..

As for other lenses, Havnt noticed anything out of the ordinary with any other lens yet.... You are correct and i have considered the possibility it is my 7D packing it up at this point (I've had it since 09, i've put like...50,000 actuation on it or so)

For now i feel its a waiting game, I dont think an issue like this simply "disappears" after the camera sits for a bit.. But until i have more info to tell Canon (And know definitively its the camera or the lens) I kinda feel i should sit on it..I'd hate to send the lens in, pay Canon to look at it, and then have the 7D pack up and be out the money i spent to have them look at an otherwise perfectly functioning lens...

I mean its not a big deal, if my 7D/100L packs up I have other cameras/lenses to play with....

c2thew wrote in post #14227937
try mashing the dof preview button to see if the aperture freezes up. Use a small f stop to make sure that the blades are closing properly.

I did that with a SIgma 70-200mm that had sticky blades. It mainly showed up when I was using my 40D with a high speed burst, but I tried pressing the DoF button repeatedly and setting a small aperture and it seemed to clear the problem

Good news is, it still seems to have the same IQ despite the little glitch up...

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