hi, since scratches usually appear on the first exposed surface, you can roughly calculate the aperture they are out of the optical path by measuring the diameter of the center section of the first surface that excludes the scratches and use the whole first surface diameter and do a simple ratio. i.e. if the center section of the first element that has all scratches excluded is one half the diameter of the entire front surface, then the aperture where the scratches are out of the optical path would be ~ two stops down. ( F8 on a maximum aperture F4 lens like the K45-125/4 ). jco
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jens Bladt Sent: Friday, March 23, 2007 8:17 PM To: Pentax-Discuss Mail List Subject: RE: SMC-K 4/45-125mm I'm not sure when the scratches get out of the optical path. The difference between F4 and F8 can be examined here: http://www.flickr.com/photos/bladt/sets/72157600018006181/show/ I don'tsee any problems, that could be asigned to the scatches for sure. Regards Jens Bladt http://www.jensbladt.dk +45 56 63 77 11 +45 23 43 85 77 Skype: jensbladt248 -----Oprindelig meddelelse----- Fra: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] vegne af J. C. O'Connell Sendt: 23. marts 2007 22:16 Til: 'Pentax-Discuss Mail List' Emne: RE: SMC-K 4/45-125mm Minor scratches will not do what you are suggesting. I my experience, when scratches become significant the cause an OVERALL loss of contrast/sharpness .eg. flare, due to stray rays, but specific halos/glows? Never seen that. What is happening in the shadow areas of your images? Are you getting visible flaring? Does stopping down to the point of getting those scratches out of the optical path change the "glowing" any or make it go away? jco -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jens Bladt Sent: Friday, March 23, 2007 5:09 PM To: Pentax-Discuss Mail List Subject: RE: SMC-K 4/45-125mm Thanks for looking JCOC. It seems like a very nice lens. It has to turned A LOT in order to focus, actually the smallest exchange rate I have ever seem on a Pentax lens. Also the focusing is very smooth, thus accurate. Only down side is the rather long closest distance - appr. 4 feet. I've seen some "glow" around white letters on black background (the shots of my AF280T flash), which could possibly be caused by the scratches on the front element (like vaseline at the edges of a filter - David Hamilton-like)o - just guessing, of course. I got this one for 40 USD at ebay - the near MINT ones seem to go for 150-200 USD. It may be a great portrat lens - 45-125 seems tobe perfect for portraits. Also F.4 all the way through the focal range is convenient for studio work. We'll see :-) Jens Bladt http://www.jensbladt.dk +45 56 63 77 11 +45 23 43 85 77 Skype: jensbladt248 -----Oprindelig meddelelse----- Fra: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] vegne af J. C. O'Connell Sendt: 23. marts 2007 18:00 Til: 'Pentax-Discuss Mail List' Emne: RE: SMC-K 4/45-125mm those scratches dont look like they would affect anything. you might want to consider filling in any large ones with black, but like I said, I bet they are small enough to not cause any visible difference. jco -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jens Bladt Sent: Friday, March 23, 2007 12:48 PM To: Pentax-Discuss Mail List Subject: SMC-K 4/45-125mm Done some test shots with the Pentax lens, which was in the mail today: http://www.flickr.com/photos/bladt/sets/72157600018006181/show/ Regards Jens Bladt http://www.jensbladt.dk +45 56 63 77 11 +45 23 43 85 77 -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.446 / Virus Database: 268.18.17/730 - Release Date: 03/22/2007 07:44 -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.446 / Virus Database: 268.18.17/730 - Release Date: 03/22/2007 07:44 -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.446 / Virus Database: 268.18.17/730 - Release Date: 03/22/2007 07:44 -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.446 / Virus Database: 268.18.17/730 - Release Date: 03/22/2007 07:44 -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.446 / Virus Database: 268.18.17/730 - Release Date: 03/22/2007 07:44 -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
