Lens Problem?

[mozzer]

Hi,

I am hoping someone can help with a problem I have on my Sigma 135-400 lens (2005) which is over exposing images for no apparent reason. All other lens work fine on my Canon 50D so its just happening with this lens.

See the pictures below, both 400/F10 yet massively different results.

Any ideas that can point me in the right direction ?





Many Thanks.

Gary

[Maisie]

I'm going to take a wild stab in the dark, Connection points might not be working properly and the camera isn't metering with that lens how it should?

Have you tried shooting in other modes, manual, av, tv etc?

[mozzer]

hi, thanks for the quick response. Yes, these were taken on tv mode, but did try manual as well with no difference. I will try cleaning the contacts & see if any difference.

Thanks.

[Heidfirst]

sticky aperture blades not stopping down properly?

[phreakf4]

sticky aperture blades not stopping down properly?

Very probably. I had a similar fault on a Sigma 50-500 (which to be fair, had been dropped!). Sent it back to Sigma for servicing via Warehouse Express (from whom I bought it) and it worked well for a while but then the fault began to recur. I finally cured it by using a tiny quantity of silicon lubricant on the actuating arm which protrudes from the lens and engages with the mechanism in the camera body. Pretty drastic and definitely not recommended unless one is well versed in such mechanical matters (and has a steady hand) but the lens has performed perfectly ever since (about 14 months ago and probably well over 10,000 frames).

[Orion]

Many years ago I had an Olympus OM10 which gave the same results. The solution was a new shutter.

Regards