Sas, I have the A1.4-S Teleconverter and it works fine with the A300/4 lens. The L teleconverters (A1.4-L and A2.0-L) are for very special applications, big fast glass. They have long snouts that won't fit in the A300/4. The L's are designed for the A300/2.8, A400/2.8, and such. I have the specs in some old Pentax literature at home. Go look at them on Boz's site.
Regards, Bob S. Sas Gabor writes: > Don Herring wrote: > > I am planning to get a 1.4-S teleconvertor, > > mainly to use with my A* 300/4. > > > > Can this particular converter be used with a > > 500/4.5 screw mount (with the > > screw mount adapter of course)? > > It can be used of course, but for these focal lengths the > 1.4-L converter is definitely a better choice.