Originally posted by Hal Davis Can anyone provide a step by step procedure for using a vintage Pentax lens on an istD body? On a K2000 body? Any differences in using a non-Pentax Kmount lens in setting up on a digital body?
Most non-Pentax K-mount lenses will work just fine on a Pentax dslr. There are two things to watch out for: the dreaded Ricoh pin, and certain Vivitar lenses.
On some Ricoh film SLRs, they added an extra pin for camera to lens communication. Unfortunately, this pin is positioned exactly where the Pentax autofocus screw drive is. The pin can become lodged in the AF drive and make the lens very difficult to remove. The good news is that the pin is very easy to remove. Be careful with lenses labelled for the K-R mount, rather than just K or KA.
Some Vivitar lenses have a shield that protects the aperture linkage lever. Pentax lenses have this as well, but on the Vivitars, it is much longer and can interfere with mounting the lens. In this case, the lens will not turn far enough to lock onto the camera. The shield bumps agains the power contacts used for the SDM motors, so it only affects K100D Super, K10D and later cameras. Again, the shield is easy to remove or modify, so as not to cause a problem.