Sigma 500 F4.5 after repair 1 stop over exposure.

Started 1 month ago | Discussions thread
ForumParentFirstPrevious
Flat view
RenG Forum Member • Posts: 96
Sigma 500 F4.5 after repair 1 stop over exposure.

I have this white version lens a few years and it got a problem with the diafragm, At 4.5 everything is OK but stopped down the diafragm got stuck and did not close or closed  not enough so huge overexposure.

Opened the back end of the lens till i could reach the diafragm itself, there was no real problem so it had to be in the mechanical parts above it. Cleaned everything and oiled it a bit with sewingmachine-oil and got it working more or less.

The problem now is 1 stop overexposure when stopped down, Overexposure is consistant so 1 stop exposure compensation works all the time but not at 4.5. So the diafragm isnt closing far enough. I have no idea if it is possible to correct this in the lens somehow? There is a ca 4cm long pin almost from the bayonet reaching down to the diafragm, bending this pin could solve the problem i think but i hope there is an easyer way??

Greetings from René

ForumParentFirstPrevious
Flat view
ForumParentFirstPrevious
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow