Re: Zeiss and Pentax coatings, lenses (similarities, differences)
If you over generalize, then yes, IF = floating element. In the case of Nikon, they refer to a floating element design, for wide angles, as Close-Range Correction (CRC). It's intended to improve performance of the lens when focused close. Aside from the single CRC element the lens focuses like a regular one. The IF lenses move groups of elements (and the group changes from one lens design to another) for basic focus. From: Fred <[EMAIL PROTECTED]> Actually, though, it is not clear in my mind, but wouldn't IF lenses be, in effect, lenses that have floating elements (inasmuch as one or more elements move relative to the other elements when focusing)? Or, to put it another way, couldn't the term be applied to any lens that moves elements (or groups of elements) differentially, compared to other elements (or groups)? Fred - 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: Zeiss and Pentax coatings, lenses (similarities, differences)
F> Actually, though, it is not clear in my mind, but wouldn't IF F> lenses be, in effect, lenses that have floating elements (inasmuch F> as one or more elements move relative to the other elements when F> focusing)? Or, to put it another way, couldn't the term be applied F> to any lens that moves elements (or groups of elements) F> differentially, compared to other elements (or groups)? F> Fred Yep, I think that IF qualifies. And they also use FREE - fixed rear element and similar designs AFAIK. Good light, Frantisek Vlcek - 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: Zeiss and Pentax coatings, lenses (similarities, differences)
> I could be mistaken, but as I can see, Pentax do not seem to use > floating element design like the other manufacturers. I know Nikon > use it. Any idea? I think that one of the Pentax lenses that may supposedly have involved some Zeiss/Pentax collaboration is the the K 28/2, which uses a floating element. Actually, though, it is not clear in my mind, but wouldn't IF lenses be, in effect, lenses that have floating elements (inasmuch as one or more elements move relative to the other elements when focusing)? Or, to put it another way, couldn't the term be applied to any lens that moves elements (or groups of elements) differentially, compared to other elements (or groups)? Fred - 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: Zeiss and Pentax coatings, lenses (similarities, differences)
>Interestingly, the article also mentions the 18mm lens >as to result from the joint development of Pentax and >Zeiss. I have never found a confirmation information >about that anywhere. However, I have a diagram of the >Contax Distagon 18/4. This shows that it's design is >exactly identical to that of the SMCP-K 18mm/3.5. The >only difference is that the Zeiss as floating elements >while the Pentax has not. I could be mistaken, but as I can see, Pentax do not seem to use floating element design like the other manufacturers. I know Nikon use it. Any idea? regards, Alan Chan _ Join the worlds largest e-mail service with MSN Hotmail. http://www.hotmail.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 .
Zeiss and Pentax coatings, lenses (similarities, differences)
Check out http://www.cdegroot.com/archives/yashicacontax-slr/199905/msg00087.html for a summary of the collaboration between Pentax and Zeiss by someone paraphrasing a book by an Asahi historian. It provides some details about how the coatings and two or three lenses began as joint developments but went their separate ways The writer summarizes the optical differences between the two companies' 15/3.5 and 28/2 lenses. No word about OCLI here; Pentax and Zeiss are credited with developing the SMC and T* multicoatings. [EMAIL PROTECTED] mail2web - Check your email from the web at http://mail2web.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 .
