Problem with the 300mm f/4 IS ???

[contrastny]

I have the 300mm f/4 IS and it's been a great lens until recently. This past weekend when I would try to use the autofocus the aperture would show "00" in the viewfinder and I could hear a clicking sound. If I let go of the shutter button and press it again it would work fine.

Has this happened to anyone? Do any of you know what problem this may be?

Thanks

 

[Mt Spokane Photography]

I'm going to assume that you have tried the usual, removing the lens, cleaning contacts, etc., and it still happens.

The 00 aperture means that the camera is not communicating with the lens to get aperture information. The clicking is likely due to the camera sending out setting information to the lens which is being followed, but not reported back to the camera. If other lenses work fine, it points to a intermittent lens issue, so it needs some repair. The problem with intermittent issues is that they never seem to happen at a camera shop.

Try the lens on a different camera, and if it does the same, take or send it for repair.

 

[contrastny]

I'm going to assume that you have tried the usual, removing the lens, cleaning contacts, etc., and it still happens.

The 00 aperture means that the camera is not communicating with the lens to get aperture information. The clicking is likely due to the camera sending out setting information to the lens which is being followed, but not reported back to the camera. If other lenses work fine, it points to a intermittent lens issue, so it needs some repair. The problem with intermittent issues is that they never seem to happen at a camera shop.

Try the lens on a different camera, and if it does the same, take or send it for repair.

Thanks for the info. I tried taking the lens off and cleaning the contacts, but as you said this only happens intermittently. All of my other lenses worked fine on the 50D body, but I'll try my 300mm on my friends camera body.

I guess I'll have to send it back to Canon at some point.