<< Hanimex used to make a 300mm mirror telephoto lens in screw mount. it wasn't a very expensive one, but it worked OK. are there any 300mm reflex lenses out there for K-mount that aren't too expensive? >>
Herb. Seek out the Sigma 300mm F4.5 Apo (from probably the 80s I suppose) or the Tamron SP 350mm F5.6 Cat. Sig for preference - a stoutly built number with APO glass. Kind regards Peter