Strange Issue= please help!

I have a canon 5d mark iii. What happens is that I will be shooting normally and then for no reason (no change of settings...) each image I shoot will appear to get darker and darker in the viewfinder and on the screen as I shoot until the image in succession is almost completely dark/black and then the camera freezes and I'm unable to click the shutter. The only thing I can do at that point is stop my session and continuously try to turn the camera off and on until it magically "unlocks" the dark screen. The only thing that unlocks it "sometimes" and is when I press the DOF button over and over and turn it off and on... For no reason I can come up with, the viewfinder will then appear bright again and I'll be able to shoot. This just doesn't seem right to me. It stops my sessions and makes me miss important moments when I'm shooting.

Has anyone heard of this problem or experienced it? Does anyone know what this might be? A weird random setting? A "dud" camera body?
Please help. Any and all constructive comments and advice welcome!
Thanks!
SC

slqc@comcast.net wrote in post #17833345
I have a canon 5d mark iii. What happens is that I will be shooting normally and then for no reason (no change of settings...) each image I shoot will appear to get darker and darker in the viewfinder and on the screen as I shoot until the image in succession is almost completely dark/black and then the camera freezes and I'm unable to click the shutter. The only thing I can do at that point is stop my session and continuously try to turn the camera off and on until it magically "unlocks" the dark screen. The only thing that unlocks it "sometimes" and is when I press the DOF button over and over and turn it off and on... For no reason I can come up with, the viewfinder will then appear bright again and I'll be able to shoot. This just doesn't seem right to me. It stops my sessions and makes me miss important moments when I'm shooting.

Has anyone heard of this problem or experienced it? Does anyone know what this might be? A weird random setting? A "dud" camera body?
Please help. Any and all constructive comments and advice welcome!
Thanks!
SC

Is the camera still under warranty?

Could you post some samples, please and your settings. Thanks

It sounds as if the aperture diaphragm in the lens is progressively stopping down as you shoot. This would be the only cause of the optical viewfinder getting darker. This could be caused by either a faulty lens or body. One thing to check would be to remove/replace the lens when this happens to see what effect that has. I would also try shooting with a different lens, if a different lens works OK then it's a lens fault, if another lens also shows the same fault, then you have a problem with your body. What lens are you using?

Alan

BigAl007 wrote in post #17833370
It sounds as if the aperture diaphragm in the lens is progressively stopping down as you shoot. This would be the only cause of the optical viewfinder getting darker. This could be caused by either a faulty lens or body. One thing to check would be to remove/replace the lens when this happens to see what effect that has. I would also try shooting with a different lens, if a different lens works OK then it's a lens fault, if another lens also shows the same fault, then you have a problem with your body. What lens are you using?

Alan

I was going to ask this too - does this happen with several lenses, or just one? If just one, is it an older lens, by any chance?

By the way, you might not want to use your full email as your user name. You can request a name change here.

By any chance do you have exposure bracketing enable? There should be a solid line under the value.

I thought of exposure bracketing too... but it's not set. I am curious about the solid line under the "value"- what value are you referring to? In the custom menu?

I'm shooting with the Sigma 35 ART lens. It's not old= have had it about 6 months. I'll test tomorrow when it's light out to see if it happens with other lenses... Haven't tried in a while but to my recollection it does happen with other lenses too. Does anyone know if Canon Repair Services will do testing with a Sigma lens if I send it in or will they only test Canon lenses in conjunction with the camera to test?

Thanks for the tip to change my user name- I just submitted the request. The lens is a new Sigma 35 ART lens...

No, the body is not under warranty anymore... I was thinking about sending it into Canon. Other than Canon, does anyone use/trust other Camera Repair shops? I'm in the SF Bay Area.

slqc@comcast.net wrote in post #17833410
I thought of exposure bracketing too... but it's not set. I am curious about the solid line under the "value"- what value are you referring to? In the custom menu?

no not the custom menu. push the info button top left corner till you get all info on picture setup you will see the exposure compensation on the screen there there should only be one one line visible under a value (- or +) if you see three bars exp. comp is set to the values underlined.

Take a couple pictures and then when it gets dark look in the lens and see if you can see the aperture blades stuck closed down...or shoot consecutive shots wide open and see if it never gets darker


Or put on a different lens to determine if its a body or lens issue

here is a shot of the screen

itsallart wrote in post #17833450
here is a shot of the screen

Hosted photo: posted by itsallart in
./showthread.php?p=178​33450&i=i188971184
forum: Canon Digital Cameras

Thanks for posting that picture. i hope they knew what i was trying to write.

I hope so too