02-28-2011, 01:14 PM
I assume you've found a darn sharp zoom lens from 70s but it's varifocal...
Lately I was checking [url="http://www.adaptall-2.org/"]adaptall lenses[/url] and on that site there's a short article about zoom lens structure. According to this article, a group called "compensator group" in coordination with the "variator group" keeps the lens in focus when zooming. So other than a solution without changing the structure would be quite interesting to read...
Serkan
Lately I was checking [url="http://www.adaptall-2.org/"]adaptall lenses[/url] and on that site there's a short article about zoom lens structure. According to this article, a group called "compensator group" in coordination with the "variator group" keeps the lens in focus when zooming. So other than a solution without changing the structure would be quite interesting to read...
Serkan