[tarsus]

For several months I have been sucessfully shooting a Vivitar 24mm prime on the Km with catch-in-focus. I have followed Robert Donovan's instructions to the letter. Suddenly, the camera began to fire whether in focus or not. I checked all the settings, in AFS, catch-in-focus on, in manual mode, aperature ring set and locked in. I put on an autofocus lens and the camera fired only when focused. I put the Vivitar back on and tried a variety of settings. The camera continues to fire regardless of focus as if it were in AFC mode. Any suggestions. Thanks.

[dlacouture]

I'd say that it's not grounding the contacts anymore...

[tarsus]

Thanks for responding. I cleaned the contacts and made sure the spring loaded pins were working properly to no effect. Could the ground simply be worn out? The lens is refurbished.

[SOldBear]

Some lenses have a coat of (commonly black) paint applied to the mount. This coat of paint is insulating.

Try a piece of aluminum foil between the camera mount and the lens, where the contacts are.

If that work, for more permanent solution, scratch the paint on the lens.

[dragonfly]

Don't you have to be in autofocus mode for manual lenses to do focus-capture?

[jboyde]

Don't you have to be in autofocus mode for manual lenses to do focus-capture?

Yes. It has to be in Af-C for focus trap.

[tarsus]

Yes, it does have to be in autofocus for catch-in-trap to work even with manual lens. My mistake. Sorry for wasting so much time. I remember now.