On Oct 24, 2007, at 10:00 AM, Tom C wrote: > Yeah I guess you're right. Those millions of SLR's sold with split > prism > screens in the 60's, 70's, 80's all had them for no good reason.
They had them for good reason, Tom: they made it faster to achieve close approximate focus. But there was never a "one size fits all" optical focusing aid that works as well as a matte screen. That's why Nikon offered as many as 30 different focusing screens with optical aids for the Nikon F line back in the '60s and '70s, with big charts to say which one to use with what lenses for what situations. Instructions for use of a focusing screen with a focusing aid always recommended that critical focus be done with the surrounding fine-matte-ground focusing surface, unless the particular screen was not equipped with any and was designed entirely to support focusing speed and brightness instead of critical accuracy. Only the matte screens (and there were three or four of those) were on the "compatible and recommended" list for all lenses. Godfrey -- 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.
