Originally posted by aurele . . . May i ask what it is and what is the problem ? Cause i'm completely puzzled !
Originally posted by Docrwm Perhaps you are serious, I can not tell
The Dreaded Ricoh pin on Ricoh lenses. I removed the pin for the first time from a Ricoh lens so it will not get stuck on my dSLRs.
this might help -
two things to watch for with certain third party older lenses:
" Several third party lens manufacturers produce or has produced lenses with a K-mount. There are no issues with current third party lenses in K-mount, but for older lenses there are two traps to watch out for:
The infamous "Ricoh pin". Where Pentax created the "KA" mount in order to support Program and Tv exposure automation, Ricoh had to create their own variant, which has a protruding pin placed in a somewhat unfortunate location, namely in the exact spot where Pentax years later placed the autofocus drive shaft. Such a Ricoh lens will get stuck when mounted on a Pentax autofocus body - the Ricoh pin will get lodged in the drive shaft and prevent the lens from being removed without deployment of finesse, patience and tools.
The other trap is the shield that protects the aperture stop down lever. The image to the left shows what the shield should look like and does look like on a genuine Pentax lens. Some older third party lenses have a much larger shield which prevents mounting the lens on a Pentax DSLR. Current third party lenses (Sigma, Tamron, Rokinon, etc.) have correctly shaped shields (or no shields) and pose no problem.
Read more at:
The Evolution of the Pentax K-mount - Articles and Tips | PentaxForums.com