I�d suppose the "crud" would become more visible if the lens is focused closer. All the best! Raimo K Personal photography homepage at: http://www.uusikaupunki.fi/~raikorho
----- Original Message ----- From: "Don Sanderson" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Thursday, July 29, 2004 4:53 AM Subject: RE: Scratch on rear element > My apologies, I should mention that this applies to a lens focused at > infinity, or FREE lenses. > May not be true for lenses with moving rear elements when focused closer > than infinity. > The 50mm I tested was at infinity focus. > > Don > > > -----Original Message----- > > From: Rob Studdert [mailto:[EMAIL PROTECTED] > > Sent: Wednesday, July 28, 2004 6:15 PM > > To: [EMAIL PROTECTED] > > Subject: RE: Scratch on rear element > > > > > > On 28 Jul 2004 at 11:58, J. C. O'Connell wrote: > > > > > not always true, if the "crud" is on the perimeter, > > > then stopping down can COMPLETELY ELIMINATE the > > > visibility of the "crud" because it is no longer > > > in the optical path. > > > > I really don't know how you come up with some of this stuff. > > Stopping down > > makes crud MORE visible, if it wasn't in the optical path then it > > never would > > have been visible at any stop in-fact it could even remotely aid in flare > > resistance. I just did a test using my patented stick on > > synthi-crud and easily > > confirmed my prior experiences, I can provide the pics if you are > > that keen. > > > > > > 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 > > >
