On Fri, 1 Dec 2006 15:36:46 -0800, Henning Wulff <[EMAIL PROTECTED]>
wrote/replied to:
You'll never convince me though that if the optical circle doesn't
need to be so
big, that the glass lenses used can't all be a bit smaller. Why do you think
medium format lenses are all so fat?
Because for the most part they're made with different criteria in
mind. Manufacturers know that people buy (bought) MF equipment for
high quality, so everything about the systems was optimized in that
direction. Weight and size were not the main concerns. Durability,
high sync shutter-in-lens are things of importance.
Yes, and the Sigma made for smaller sensors is made with different criteria in
mind, that's my point. It's made for someone who wants a thinner,
lighter lens.
That is the design objective they start off with and I guess they
manage to trim
it down considerably. Otherwise nobody would buy it.
We haven't touched the optical laws of physics here though, about making a
bigger image circle. I guarantee you it requires bigger glass not smaller and
vice versa.
--
Jim Davis, Owner, Eastern Beaver Company:
http://easternbeaver.com/ Motorcycle Relay Kits,
Modulator Kits, Powerlet, Centech, Posi-Lock, Parts.
1988 K100RS SE ABS in Japan. 1991 ST1100 in America.
STOC#6327, IBMWR, KBMW
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Image circle and size of glass are not interdependent. Look it up
since you clearly don't believe me.
--
* Henning J. Wulff
/|\ Wulff Photography & Design
/###\ mailto:[EMAIL PROTECTED]
|[ ]| http://www.archiphoto.com
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