[LargeFormat] assignment: Portrait

[Richard Knoppow]

----- Original Message ----- 
From: "LNphoto" <LNphoto@twmi.rr.com>
To: <largeformat@f32.net>
Sent: Monday, December 01, 2003 1:41 PM
Subject: Re: [LargeFormat] assignment: Portrait


> Sorry for the bad link, glad somepeople figured it out
> http://home.twmi.rr.com/lnphoto/pairofslrs.jpg
>
> I bought the Press Graflex as more of a parts camera than
anything
> else, the seller didn't know much about it. When it
arrived I
> pairtially disassembled it and found a shutter in
amazingly good
> condition, has to have been a replacement.   The spring is
a little
> weak but I hope to be only a little weak after 80+ years.
The Dagor is
> in great shape after a bubble bath. It'll take a little
fussing to shim
> up the plate septums of the bag mag to accept film, but
I'm going to
> give it a shot.
>
> Les
>
> On Monday, December 1, 2003, at 03:50  PM, David Galway
wrote:
>
  The spring tenstion can be adjusted. I am not sure if the
Press-Graflex works like the Series-B and Series-D, and
Speed Graphics, but in all three its possible to wind the
resting tension of the spring by removing the screws holding
the plate of the tension adjustment knob and turning the
whole thing.
  The spring also probably needs some lubricating, you can
squirt some light machine oil down the inside of the tube.
  Note that Graflex shutters do not match the speeds on the
chart except in a a few places. The highest speed is very
optimistic and if tensioned up to make it actually the
listed speed, the lower speeds will be off.
  Also note that measurement of focal plane shutter speeds
must be done carefully. Despite the popular wisdom to the
contrary FP shutters are not very efficient. The effiency
varies with the ratio of slit width to distance from shutter
curtain to film and with the angle of the cone of light from
the lens. In general, the shutters are more efficient for
long focal lengths and small f/stops. Since the marked
speeds are based on average efficiency measurements of total
open time will show slower speeds the same as with between
the lens shutters.
  Graflex shutter are also not constant speed accross the
film. They tend to accelerate so that the bottom of the film
(top of the image) gets less exposure than the other end. At
the highest speed the difference can be a full stop.
  The story is that Press Graphics were the standard press
photographer's camera until the late 1920's. At that time a
New York Times photographer was killed covering an
automobile race because he had is face in the finder hood
and didn't see an on-coming car. The Times said no more
Graflex's so there was a fairly rapid switch to Speed
Graphics, then a new model.
  The story may be apacrophal and I can't remeber where I
first read it but somehow think it was a relaiable source.

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com