I have a 50 f1.4 FD, 52mm filter size, non-breechlock, serial 984909. It displays a slightly different behaviour to any other lens in my collection. When set to the full aperture of f1.4 the aperture blades stop down a small amount, less than that to the adjacent 1/2 stop setting of f1.8, both when the stop down lever is pressed and when taking a photograph. So, I only get true full aperture (whatever that is) when viewing. Is this some sort of full aperture flare reduction feature or is my lens in need of a service? Apart from this feature, the lens is in good condition and the aperture blades are perfectly clean, and operate smartly. (The bayonet ring doesn't rotate slightly when fitting the lens to a camera body.) Thanks for any insight.

-- Malcolm Stewart (malcolm_stewart@megalith.freeserve.co.uk), February 08, 2002

Answers

Malcolm,

The aparture blades should not move when you stop down at f1.4. Mine doesn't. It seems that the aparture needs a adjustment.

Kettil

-- Ketil Johansen (ketiljo@stud.ntnu.no), February 09, 2002.

Many thanks for the quick reply. I guess I now know partly(?) why it was cheap! I'll have to give it a try out, and check whether the error propagates down to other apertures.

-- Malcolm Stewart (malcolm_stewart@megalith.freeserve.co.uk), February 09, 2002.