Hi! I am sorry I am a little late. My reply is between the lines.
ein> 1) make it better (sharper, better corrected, etc) That's what is most unclear to me. You see, as far as I understand the enlarging from 35 mm film is limited. You can enlarge at 10x may be 12x, normally not more than that. Perhaps William Robb will correct me here. But anyway, there is a well known general limit on enlargement. So, if you have a lens that gives you enough sharpness all the way through to the limit, why to want more? This is exactly that puzzles me. Lenses are not like computers and cars. You can throw them at the test chart <grin> and once you reach your objective, you're quite done with them. That's why old lenses are so popular among our kind. At least so I think. ein> 2) make it smaller or lighter This is reasonable thing to do. But to take an example, my M 50/2.0 or FA 50/1.7 are roughly of the same size and weight. And K 24/2.8 is actually smaller, way smaller than its modern counterpart. Though it is said (I did not experience it myself) that modern lens is sharper, particularly in the corners... I don't have too many lenses and those I have are not rare. Hopefully one day I will get to meet some fellow PDMLers that would allow me to at least look at their glass. Then perhaps my view would change. I know I can take a long walk through Boz's site, but here seeing is believing... I mean, seeing it for real. ein> 3) make it cheaper to manufacture But it does not have to be new optical design, does it? ein> 4) incorporate new technology not availible before (special glass, ein> vibration reduction, aspheric elements, internal focusing), ein> usually to do one of the first 3 things on the list. This would require rigorous statistical research to be performed. I think that most of what you listed above applies to zoom lenses. But I agree. I can see only one reason that would force Pentax or other company to produce new lenses. That is one that seems clear to me. It is the production of new class of lenses by competition. Say, 24-90 was I think partly developed and eventually produced in response to other companies offering 24-xx lenses since recently... Same goes for most recent lenses for *istD. ein> Basically, lens design is all optical physics. You can do it all as a ein> mathematical exercise, but it is a very complex one. Computers excel ein> at laborious math. Yes of course. Well, I wonder how much computers participated in design of my Soligor 70-222/3.5 zoom. Arguably, Pentax SMC F 70-210/4-5.6 is better on compatible aperture values... Boris ([EMAIL PROTECTED] or [EMAIL PROTECTED])
