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From: mather@uicsl.UUCP
Newsgroups: net.rec.photo
Subject: Re: Zoom lens comparisons
Message-ID: <11900005@uicsl>
Date: Sun, 15-Dec-85 15:24:00 EST
Article-I.D.: uicsl.11900005
Posted: Sun Dec 15 15:24:00 1985
Date-Received: Wed, 18-Dec-85 02:46:48 EST
References: <632@wjvax.wjvax.UUCP>
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Nf-ID: #R:wjvax.wjvax.UUCP:632:uicsl:11900005:000:1013
Nf-From: uicsl.UUCP!mather    Dec 15 14:24:00 1985


Zoom lens suffer from 3 problems:
	1) weight	(more elements needed for the range of focal lengths)
	2) distortion   (caused by the added lens groups)
	3) speed        (they are typically a few stops slower than tele's)

However, the newer designs have really made an impact in all 3 of these
areas. They lens designers are now pushing those optics programs (FORTRAN?)
to design V E R Y   W I D E   A N G L E  lens which are light, fast and
clear. I haven't bought any of these ultra-wides, but have read that the
weight problem still exists and you may find the focus-zoom feature annoying.
I bought the Vivitar Series I 28-90 f2.8-3.5  and the lens does NOT stay
in focus as you zoom. This is typical of fast zooms, but I find it a pain
compared to my Vivitar Series I 70-210 f2.8-4.0 which I can focus at the
farthest focal length (210) and then zoom back for optical framing.
I personally still opt for two zooms of slightly overlapping range.
----
				b.c.mather
				Software Surgeon
				uiucdcs!uicsl!mather