Another Big Old Brass lens to try-- Emil Busch Rapid Aplan..

"Jos. Burke" <josburke.DeleteThis@bellsouth.net> wrote in message news:<dpxGc.22880$w56.117@bignews1.bellsouth.net>...
 > I have acquired another big brass lens: An Emil Busch Rapid Aplanet No.
 > 5 Foc. 18 ins. (R.O.J.A. vorm Emil Busch A-G Rathenow). Built in iris with
 > f/8 thru 64 settings.
 > It came attached to a Thornton Pickard shutter that seems to function
 > properly. The Shutter and lens assy was a direct fit onto my Seneca
 > 11x14--so I mounted it and focused to get an idea of its coverage. I was
 > really surprised as it appears to cover the full 11x14 format even at f/8
 > ( to focus at least !) on the GG. It also appears rather sharp with very
 > good definition on the GG as well. I am interested in adapting to a packard
 > shutter as that Thornton Pickard thingy is vibration infested-I wonder how
 > users ever got a sharp image with that roller blind "clunking" contraption.
 > Any insight on this lens--sharp--yes/no!! Original uses??
 > Richard K.??????
 > Thanks J Burke

I haven't used the Thornton Pickard shutter, but I have used Graflex
focal plane shutters, on Speed Graphics, Graflex SLR's, and an 8x10
unit on my 8x10 view camera. Vibration has never been a problem that
has resulted in unsharp pictures for me. I think the reason is that
the main vibration results when the shutter curtain stops moving
abruptly. By that time the picture exposure is done. Also, remember
that only a small strip of film is being exposed at any given time in
the exposure process.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Another Big Old Brass lens to try-- Emil Busch Rapid Aplan.. 

"Jos. Burke" <josburke.RemoveThis@bellsouth.net> wrote in message
news:dpxGc.22880$w56.117@bignews1.bellsouth.net...
 > I have acquired another big brass lens: An Emil Busch
Rapid Aplanet No.
 > 5 Foc. 18 ins. (R.O.J.A. vorm Emil Busch A-G Rathenow).
Built in iris with
 > f/8 thru 64 settings.
 > It came attached to a Thornton Pickard shutter that
seems to function
 > properly. The Shutter and lens assy was a direct fit onto
my Seneca
 > 11x14--so I mounted it and focused to get an idea of its
coverage. I was
 > really surprised as it appears to cover the full 11x14
format even at f/8
 > ( to focus at least !) on the GG. It also appears rather
sharp with very
 > good definition on the GG as well. I am interested in
adapting to a packard
 > shutter as that Thornton Pickard thingy is vibration
infested-I wonder how
 > users ever got a sharp image with that roller blind
"clunking" contraption.
 > Any insight on this lens--sharp--yes/no!! Original uses??
 > Richard K.??????
 > Thanks J Burke
 >
 >
The Rapid Aplanat is a Rapid-Rectilinear. These were sold
under many different names. R-R's are capable of very good
performance but are not anastigmat lenses. The astigmatism
is compensated by introducing some field curvature to
average the curvature of the radial and tangential fields
around the focal surface. The effect is minimised by
stopping down, while the aperture has no effect on the
astigmatism itself it does increase depth of field so the
aberration has less effect. Because these are symmetrical
lenses they have little lateral color, distortion, or coma.
Other aberrations depend on the exact design but Busch was a
quality lens maker so its likely a good example of the type.
Thornton-Pickard was an English company who made high
quality view cameras and had a patent on a type of roller
blind shutter. They made both focal plane shutter adaptors
for their view cameas and front or rear of the lens shutters
using the same slit curtain principle. Unlike a curtain type
focal plane shutter the roller blind shutter on a lens
exposes the entire film at once, or at least in broad
segments if the slit is narrow. Its possible to use a
Packard shutter but the Thornton-Pickard, if its working,
gives you a choice of shutter speeds where the Packard does
not.
The Rapid-Rectininear was invented simultaneously and
independantly by H.A.Steinheil and J.H.Dalmeyer in 1866.
Steinheil called his lens the Aplanat, Dallmeyer the Rapid
Rectilinear. These lenses became immensly successful and
became one of the most widely used lenses in photography,
being replaced by other types only after the development of
"Jena" glass around 1890. Jena glass allowed the
construction of lenses which were simultaneously corrected
for color and astigmatism. The Rapid Rectilinear type
continued to be made until the early 1930's for use in lower
cost folding cameras. Bausch & Lomb built millions of them
for Eastman Kodak, mostly calibrated in U.S. stops.


--
---
Richard Knoppow
Los Angeles, CA, USA
dickburk.RemoveThis@ix.netcom.com<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Another Big Old Brass lens to try-- Emil Busch Rapid Aplan..