[LargeFormat] Wollensak 15" Telephoto (was re: Shooting Landscapes with 305mm)

[Richard Knoppow]

----- Original Message -----
From: "Stuart Phillips" <stuart.phillips@rcn.com>
To: <largeformat@f32.net>
Sent: Sunday, April 20, 2003 10:29 PM
Subject: Re: [LargeFormat] Wollensak 15" Telephoto (was re:
Shooting Landscapes with 305mm)


>
> , and Enlarging Raptars are awful. >
> > Richard Knoppow
> > dickburk@ix.netcom.com
> > Los Angeles, CA, USA
>
> What about Wollensak enlarging Velostigmats? I have a 3.5"
f4.5 that looks
> like it's a 29mm thread. I always wondered about having a
step-ring made for
> it so I could use it in a 39mm enlarger.
>
>
  I just don't know. Wollensak used the name "Velostigmat"
until about 1946 when they changed to Raptar, which I guess
was supposed to be more "modern". Somewhere I have an old
magazine announcing the name change. Wollensak held a
contest and Raptar was supposed to be the winning entry. Who
knows?  Wollensak started coating lenses about the time the
name was changed. They, along with Kodak, were among the
first manufacturers to coat lenses routinely, and to use
synthetic cements in place of Canada Balsam.
  Their lenses _should_ be excellent, but some just are
dogs. I have no idea why, it doesn't seem to be a quality
control problem but rather some design problem. Perhaps they
got bad glass occasionally. I would like to hear from anyone
with an Enlarging Raptar or a 135mm, f/4.5 Raptar with good
performance. The Raptar, also sold as an Optar, has
excessive coma. While the center of the image is very sharp
the corners are just bad until the lens is stopped down to
f/22 or smaller. The Kodak Ektar, 127mm, f/4.7 OTOH is has
no noticable coma at the corners of a 4x5 at f/8. The same
for the Zeiss Tessar 135mm, f/4.5, once the standard on
Speed Graphics.
  Maybe I got some bad examples, it would be interesting to
know.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com