Originally posted by Clinton Sigma makes a 135/1.8?
They used to make one in the ys mount (T-mount with aperture control).
The ys-Pentax-k mount was specially installed at the factory and was not available to buy seperately. The ys-Pentax-k mount was also specific to what aperture range a lens had.
Another thing of note is that the ys-whatever mounts were not the same in between lenses. The one for my 135/1.8 has a single arm coming out of it that attaches to the lens, while my 300/4 has two arms that come out and attach to the lens.
Mine were both for Canon, so I am just using a t-mount adapter currently.
I want to make an actual modified t-mount adapter that will allow me to use stop down metering instead of having to use it as a fully manual lens, especially for the higher f-stops.