[LargeFormat] assignment: Portrait

[LNphoto]

On Monday, December 1, 2003, at 10:41  PM, Richard Knoppow wrote:
> 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.

<snip> I'll give that a shot, I certainly don't see where I need the 
upper speeds, never used the 1/1000 on a Speed Graphic yet, don't know 
why or how I'd use 1/1500.  I suppose with 400 speed film and a Ic 
Tessar....
But I didn't notice that I can't get the spring to get as low as 
tension #1.  The tension numbers are odd (appropriate for an F&S 
camera) and run from 1 to 15.  So I may do some fiddling but I'm gonna 
try shooting it as is first..
>   The spring also probably needs some lubricating, you can
> squirt some light machine oil down the inside of the tube.

Not sure what you mean by "tube". All of my clock repair buddies prefer 
graphite powder on their springs.

>   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.

So what's the best way of testing this flivver? i have a Calumet 
digital shutter tester.
Can't I just stick it up next to the shutter without a lens and a nice 
40w lamp at the other end?
After all, the tester will show what that area of the film got for an 
exposure, won't it?
Granted I'd have to test multiple spots multiple times to see any trend 
of under exposure at the bottom, but won't that get me in the ball park?

How should it be done?

>   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.

Which is/was good as the old plates were blue sensitive and over 
exposed the sky.

>   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.

while it might not have been an auto race or the guy at The Times, I'm 
certain somebody got hurt because they couldn't see what was around 
them. And even if they did see something coming, this thing puts you in 
a position that you can't jump very quickly.
>
> ---
> Richard Knoppow
> Los Angeles, CA, USA
> dickburk@ix.netcom.com
>
>
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