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 .
