[Edgar_in_Indy]

My father-in-law frequents auctions, and recently he picked up very cheaply an old Canon AE-1 with an FD 50mm 1.8 lens attached. He wants me to sell the camera/lens on eBay, so I'm trying to check to see if everything is working. The lens and body look like they're in great shape, but when I have the lens off the body and adjust the aperture ring, the aperture blades do not move.

There are two levers on the back of the lens, a large one and a small one. I am able to easily move the large one with my finger, but the blades do not move. The small lever does not move when applying light pressure.

So is this lens broken, or is there something I don't know about these old FD lenses?

Thanks for any help!

[boriscleto]

The lens has to be on the body for the blades to move.

If you look under the mounting ring you will see a small button half covered by the ring. It should be right under the red dot. If you depress that the ring will unlock and you will be able to use the aperture lever to close the blades.

[L33tGreg]

Does the camera have a DOF preview? This would be an easy way to test if it stops down correctly.

[Edgar_in_Indy]

Thank you both for your help. There is indeed a DOF preview, and when using it the viewfinder gets noticeably darker and the depth of field increases, so I guess the lens is working.

[tibbitts]

I'm glad your lens turned out to be working. I have a 50/1.8 FD that suddenly ceased closing down (mounted or not); these lenses will normally close down when removed from the camera. Being broken makes the lens quite handy as a magnifying glass (normally you'd need a reversing adapter on the back end of the lens to allow the aperture ring to control/open the blades when off camera or reverse mounted), but not much good for anything else. In any case, it is definitely possible for this lens to malfunction in the way you initially described.

Paul