Been trying to find a way to get an auto aperture macro setup, as my current 'dummy' extension tube will mean that the aperture closes down as I stop down the aperture. Auto extension tubes for Pentax seem to be rare and the ones that I can find are expensive.
I got a 2x teleconverter from ebay with auto aperture and removed the lens element. This becomes a ~25mm auto extension tube. Next I taped up the rear that touches the k-mount contact pins with metal tape to allow stop down metering. Combining this with the Pentax 1.7x AF teleconverter, I managed to get a "near point" auto focus, auto aperture, setup.
Here is a sample 50mm+extension tube+1.7x AF teleconverter
Guess where is this?
I got a 2x teleconverter from ebay with auto aperture and removed the lens element. This becomes a ~25mm auto extension tube. Next I taped up the rear that touches the k-mount contact pins with metal tape to allow stop down metering. Combining this with the Pentax 1.7x AF teleconverter, I managed to get a "near point" auto focus, auto aperture, setup.
Here is a sample 50mm+extension tube+1.7x AF teleconverter
Guess where is this?