Re: lens formulas for pentax lens.
Thanks for the info. --- Yoshihiko Takinami [EMAIL PROTECTED] wrote: Hi, At 5 Feb 2001 07:30:06 -0800 (PST), Richard Saunders [EMAIL PROTECTED] wrote; Tessar's are four elements, is the M50/4 macro a four element lens a Tessa? It seems one of these designs commonly known as Tessar type. The FA28-70/4 has a remarkable resemblence on MTF curves at photodo.com to the Angeleux 28-70/2.8, I believe the Angeleux were orginal designs. No. FA28-70/4 is an original design by Pentax. I believe the FA50/1.4 is a standard formula with a name? It is one of the designs known as double Gauss type, a very usual design for normal lens. And Pentax's Super- Takumar 50/1.4 was one of the first designs of this type. Needless to say, it is Pentax's original design. The FA100/3.5 Cosina? FA28-105 (new) and FA28-200 were these orginal Tamron design's They are just OEM lenses for Pentax. Most Petax lenses are original design by Pentax. Hope this helps. -- Yoshihiko Takinami Osaka, Japan [EMAIL PROTECTED] - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org . = Regards Richard Saunders __ Do You Yahoo!? Yahoo! Auctions - Buy the things you want at great prices. http://auctions.yahoo.com/ - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: lens formulas for pentax lens.
Yoshihiko Takinami [EMAIL PROTECTED] wrote: - At 5 Feb 2001 08:56:50 -0800 (PST), Alexander Krohe [EMAIL PROTECTED] wrote; The 15mm/3.5, the 18mm/3.5 and the 28mm/2 (K-series) designs are (almost) identical to those of the corresponding Zeiss/Contax lenses. I think, however, most Pentax lenses are original designs. It seems well known that 15/3.5, 28/2, and 45-125/4 were the major results of co-working with Zeiss in early 70's. - Hi Yoshihiko, thanks for the information. From a book that I have, which shows all Contax/Zeiss lens designs, also the design of the 18/4 Distagon appears to be identical to the design of the SMC 18/3.5 (except that the Distagon has floating elements to improve image quality at close distances). This is nowhere documented, but I guess the SMC 18/3.5 might have an aspherical element (I have this lens and I can't see noticable coma wings around light sources at the image corners shot wide open, which I think is quite remakable for such a lens). Do you know something about that? best wishes, Alexander __ Do You Yahoo!? Yahoo! Auctions - Buy the things you want at great prices. http://auctions.yahoo.com/ - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: lens formulas for pentax lens.
Hi Collin, At 05 Feb 2001 19:44:21 -0500, Collin Brendemuehl [EMAIL PROTECTED] wrote; My understanding of the double Gaussian design' failure (from the lens design sites) was that it produces bad bokeh. I do not think so. A well designed double Gaussian type lens produces very good bokeh, such as those of FA35/2AL at f/4, Summaron 35/3.5 at f/5.6, FA43/1.9 Limited at f/4, Voigtlander Septon 50/2 at f/5.6, FA77/1.8 Limited at f/4, and so on. But that's just my feeling. -- Yoshihiko Takinami Osaka, Japan [EMAIL PROTECTED] - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
lens formulas for pentax lens.
Can anyone help with Pentax lens and are they design formula orginal's or based on another. Tessar's are four elements, is the M50/4 macro a four element lens a Tessa? The FA28-70/4 has a remarkable resemblence on MTF curves at photodo.com to the Angeleux 28-70/2.8, I believe the Angeleux were orginal designs. I believe the FA50/1.4 is a standard formula with a name? Any others? The FA100/3.5 Cosina? FA28-105 (new) and FA28-200 were these orginal Tamron design's = Regards Richard Saunders __ Get personalized email addresses from Yahoo! Mail - only $35 a year! http://personal.mail.yahoo.com/ - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: lens formulas for pentax lens.
My understanding of the double Gaussian design' failure (from the lens design sites) was that it produces bad bokeh. Collin At 07:34 AM 2/6/01 +0900, you wrote: It is one of the designs known as double Gauss type, a very usual design for normal lens. And Pentax's Super- Takumar 50/1.4 was one of the first designs of this type. Needless to say, it is Pentax's original design. -- Yoshihiko Takinami *** "The accumulation of all powers legislative, executive and judiciary in the same hands . . . may justly be pronounced the very definition of tyranny." --James Madison, Federalist 47 - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
