Interesting. Could you elaborate even a little? I´d say using polymer layers to create
aspherics is the easiest and cheapest way of making them. It appears to be limited for
not-so-extreme curvatures, too. BTW do you have any information about Canon using
plastic elements in SLR lenses in the ´seventies?
All the best!
Raimo
Personal photography homepage at http://personal.inet.fi/private/raimo.korhonen
-----Alkuperäinen viesti-----
Lähettäjä: Mike Johnston <[EMAIL PROTECTED]>
Vastaanottaja: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
Päivä: 29. tammikuuta 2001 5:01
Aihe: Plastic Crap Lenses or High-Tech Precision?
>Raimo wrote:
>
>> What do you mean with the statement "it's the least accurate" - we are talking
>> about very small tolerances, about 1/1000 of millimetres here. The polymer
>> layers are that thin. Do you have any data to verify your conclusions?
>
>Raimo,
>No, I'm a journalist, not a scientist, so I have _sources_ to verify my
>conclusions. <g>
>
>A good deal of what I've heard about aspheric lenses was told to me by Chuck
>Westfall of Canon, who asked the lens designer in charge of aspherical
>optics at Canon Tokyo some questions on my behalf, and who then wrote a very
>complete and valuable primer about aspherics in an e-mail to me three or
>four years ago. For two years I tried to get him to expand that e-mail into
>an article for _PHOTO Techniques_, but he could never get the necessary
>clearance from Canon. Unfortunately, I'm not at liberty to share Chuck's
>e-mail (or at least I was asked not to publish it, and I'm not going to
>split those hairs).
>
>--Mike
>
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