On Tue, Apr 19, 2011 at 04:35:24PM -0400, Sam L wrote: > On Sun, Apr 17, 2011 at 11:34 PM, Stan Halpin > <s...@stans-photography.info> wrote: > > > > And where are the DA 1.4 and DA 2.0 tele-extenders?!? > > Would it be crazy to ask for a DA 1.0 tele-extender? > > That would allow me to use my old lenses at their nominal focal length > and give me a bit of auto-focus, right?
Not without a whole lot of other compromises, no. Teleconverters work, in essence, by attaching behind the lens and shifting the image plane of the lens backwards. The amount of shift is directly related to the "magnification" (or, alternatively, narrowing of the angle of view). You can do this by, effectively, sticking a concave lens behind the lens. And that's what a teleconverter is, really. A 1.0x tele-extender would have to leave the angle of view the same. That doesn't leave any room to insert a simple design between the lens and the camera. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
