I just received a New FD 100/2.8 lens that I purchased at Ebay auction from someone in Texas.

The lens stays fully open at F2.8 even when I put the camera into stop-down mode.

I have emailed the seller asking for a refund.

Does anybody have any simple ideas of how to possibly unjam this lens?

-- Howard Z (greenspun@howardz.com), March 06, 2001

Answers

Probably oil on the blades. If it's otherwise a good lens and you didn't pay too much for it, it is probably worth the $50-80 you would spend to have it professionally cleaned and lubricated.

-- David Goldfarb (dgoldfarb@barnard.edu), March 06, 2001.

Do the blades remain wide open when the lens is dismounted? They lock at something like f/5.6 when the mount rotates off the camera. I bought a 135 once, and the lever at the bottom of the mount that closes the blades for exposure, and via the stop down lever, was bent ever so slightly and in a bind.

-- Alan Swartz (swartz@tyler.net), March 06, 2001.

sometimes aperture only closes down to the aperture you shot last time. Try releasing shutter at smaller aperture.

-- pil joo (gjoo@po-box.mcgill.ca), March 07, 2001.

The lens is wide open under all circumstances. When off the camera, when on the camera, and when depth of field lever is pressed.

Fortunately, the Ebay seller says he will refund my money. So I plan to mail it back to him tomorrow.

-- Howard Z (greenspun@howardz.com), March 07, 2001.