You are thinking about it backwards, Mark. If the lens flange to focal length distance is longer you need no optical element. (Just place it farther away from the body). For lenses with shorter focal lengths, an adapter that adds thickness has to add an optical element to attempt to adjust the focal length distance from the original to the new longer focal length. That doesn't usually work well for image quality.
On Wed, Sep 17, 2014 at 10:15 AM, Mark Roberts <[email protected]> wrote: > http://www.bhphotovideo.com/c/product/995307-REG/fotodiox_fd_pk_g_pentax_k_camera_lens.html > > It does contain a glass element. > Probably crapifies images pretty well. > > I have onw for putting Pentax lenses on my Sony Alpha body; I took the > glass out and use it only for macro work. > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. -- Photographers must learn not to be ashamed to have their photographs look like photographs. ~ Alfred Stieglitz -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
