HI all. I recently added a Chinon MCL 200mm F3.3 lens to my collection, and tried it out for the first time today. I'm having a problem with it, and hope those in the know here might be able to advise me!
The lens is entirely manual and is, allegedly, compatible with K mount cameras. The aperture ring rotates and clicks smoothly and positively, and - with the lens not mounted on the camera - controls the aperture correctly. Moving the aperture lever back and forth on the lens mount causes the aperture to open up and stop down as expected.
I'm using "M" mode, with the camera set to allow use of the aperture ring, and all of my other manual lenses work just fine. With the Chinon mounted on the camera (either the K3 or K5), the aperture is fully open, but when I press the green button to meter, or use the DOF function on the camera for the same purpose, the lens doesn't stop down - I hear nothing at all, and see no movement whatsoever.
The mount on the Chinon is black (painted or anodised) whereas my other lenses have unpainted mounts, and I'm wondering if this may be the issue. I've read of situations where people scraped off the paint on the lens mount to complete an electrical circuit on their Pentax DSLRs.
Can anyone shed any light on this? I've attached a pic of the lens mount...
Many thanks
Mike