Hi

Sorry for the basic question, but I have just bought an adaptor to mount some Contax Zeiss AE lenses on my Canon 1DS camera. The problem is that the diaphragm doesn't close when I try to modify the aperture ring on the lens, and the lens remains wide open... is that normal? I find it pretty frustrating and I wonder how to use the lenses anyway... do I need to mount and remove the lenses every time I want to modify the diaphragm?

Thank you very much!!!

Dario

To change the aperture on the Contax lens, use the aperture ring on the lens. I know that's a very basic statement, but some people expect the aperture to change as they turn the dial on the Canon body. We all wished it worked that way

The next possible issue is that the little "arm" on the back of the lens is catching on something inside the Canon mount. On the back of the Contax lens there are some levers which are the mechanical linkages to change the aperture setting. Hopefully this picture will help:



The tiny arm is mostly likely hanging on the pin block in the Canon 1Ds. Here's what I mean by "pin block":



Fortunately the fix is very simple - file down the actuator a tiny bit. I've used a Dremel tool for such operations and it takes about 30 seconds. Check out this section in the Contax 100mm F2 Planar review for more info on filing down the offending actuators / fins:

http://www.pebbleplace.com/Personal/Contax_100mm_Planar_Pt_II.html

Before starting this fix, just make sure the aperture works correctly when the lens is NOT mounted to camera. This will rule out any mechanical issues with the lens itself.

Good luck and I hope this answers your question.