On 28 Jul 2004 at 19:35, J. C. O'Connell wrote: > You don't seem to have a clue as to how lenses work > especially with regard to the diaphram. As you stop > down the diameter of the optical path is reduced > proportinally. If there are scratches , etc on the > ***perimeter*** of the rear element and the lens is stopped down enuff > taking > the angle of view into account, the "crud" on the > perimeter is often COMPLETELY OUT OF THE OPTICAL PATH, I.E. IT IS > IRELLAVANT AND HAS ZERO AFFECT ON THE IMAGE FORMED > BY THE LENS!
Slapping myself for even getting sucked into responding to JCO :-( David, when you come over next we will determine experimentally if it does or doesn't have an effect. Unfortunately I doubt that Kennedys will want anything at all to do with it particularly WRT replacing rear elements. I'll have a go repairing it and if I break it I'll replace it. Cheers, Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://members.ozemail.com.au/~distudio/publications/ Pentax user since 1986, PDMLer since 1998
