----- Original Message ----- From: "Tom Rittenhouse" > > For general photography there were (are) very few lenses that meet the > optical definition for apocromatism. The various manufacturers use their own > definition for how far off the focus for each color can be, and very few of > them publish that definition. Most, if not all, depend upon depth of focus > to make up the difference.
I challenged a Minolta rep on this very subject once. The answer I got was that if the 3 measurement colours (they used the middle of the RGB, ) were focused at the same plane within the depth of focus of the lens, then they felt it was an APO lens. I thought the definition was a bit loose, but then, I don't use Minolta, either. William Robb - 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 .
