50/1.7 lens

Today i got my hands on one of these lenses - but I have a small problem It is the M version, and I'm pretty sure the stops work correctly because when the lens is off the camera I see the iris change when i turn the ring. However, when the lens is on the camera, turning the aperture ring does't have any effect on the aperture

So i'm stuck at f1.7.

Great results at this aperture, but having the full use of the lens would be nice. Do I have a faulty lens or is there something elementary that I may be doing wrong?

The lens should only stop down when you take the photo (or take an exposure reading, with the green button, or depth of field preview), and assuming you're using it on a DSLR, you'll only be able to use it when the camera's set for manual exposure. If you use any other mode (Av, Tv or P) the iris won't close until after the shutter has fired.

You'll also need to enable the camera to use lenses that don't have an 'A' setting - you do this in the camera menu somewhere.

If your 'ist' is a film ist, someone else will have to answer you, as I don't have any experience of that body.

Hope that helps,
Dan

Thanks v. much for the quick reply - thats exactly it - i wasn't in manual mode. Everything is working as it should now I'm dead chuffed - it is good condition and only cost me a tenner at a pawn brokers shop!