Re: Speed Graphic Focal Plane Shutter
Quote:
Originally Posted by
Rider
Can that be installed in a Speed Graphic?
A Speed Graphic has a shutter. But the activity I wanted to support was using barrel lenses not mounted in a shutter, and selected the Speed Graphic to support that because it also supported the separate activity of a fun, hand-held large-format camera. The Sinar shutter is for the Sinar, which is my main large-format camera.
Rick "being goofy with the Speed" Denney
Re: Speed Graphic Focal Plane Shutter
I looked for the link for the overhaul / service manual at graflex.org and could not find it. Do you have a link?
Thanks in advance.
d.s.
Re: Speed Graphic Focal Plane Shutter
Quote:
Originally Posted by
d.s.
I looked for the link for the overhaul / service manual at graflex.org and could not find it. Do you have a link?
Thanks in advance.
d.s.
Look on www.southbristolviews.com
Re: Speed Graphic Focal Plane Shutter
Re: Speed Graphic Focal Plane Shutter
In reading the instructions for the FP shutter, it says in para d), ...
With the bottom strut of the curtain 1/4 inch from the upper, inside edge of the frame, ...
This is the "O" opening it's talking about and I know what the struts are but whats the "inside edge of the frame"? and why the bottom strut?
In a later paragraph, j), it says...
Check the distance of the top strut of the open aperture from the top inside edge of the case. If this distance is not 1/4 inch from the bottom of the curtain strut to the upper, inside edge of the frame it will be necessary to blah blah...
Whats the edge of the case, and whats the edge of the frame.
What am I measuring 1/4 inch to?
I sounds like the top strut is to be 1/4 inch above the film gate, and the bottom strut is to be 1/4 inch below the film gate. I'm using "film gate" to mean the opening in the back that the light shines through to the film.
Any insite to this is appreciated. Thanks,
d.s.
Re: Speed Graphic Focal Plane Shutter
Got it together and it works. 30/50 are good, and the rest are as others above in this thread have stated. Now to shoot film.
d.s.
Re: Speed Graphic Focal Plane Shutter
I eventually got round to doing this. I used Steve's circuit (below), using a BC107 for Q2 and a TEPT5600 phototransistor, which is sensitive in the visible range, rather than IR which seems to be the case with commonly available phototransistors. I don't know if there's any advantage to using a visible sensitive device, but it seemed right to me at the time. The trimpot is set at roughly centre of its range. Supply is 6 V (4xAA).
I use Sound Studio rather than Audacity, only because I already have it for digitising vinyl recordings; it's pretty much the same. A typical trace is shown for my 8/120 Angulon at 1/50 sec (Compur 0 shutter).
Rather than a single waveform representing the duration of shutter opening, I get two spikes representing the opening and closing of the blades. I also get the same for focal plane shutters.
The good news is that my lenses are all good enough - all within about 1/4 stop at speeds I most often use, running slower at speeds of 1/250 and above which I seldom use.
One unusual thing I noticed is that an old Symmar I have in a Prontor 00 has no click-stops on the shutter speed dial. I don't know whether this is common, I haven't seen it before. The lens presumably came with cam and camera, a 6x9 Linhof Technika which Bob Salomon kindly dated for me as 1948. Doing a couple of runs with this lens showed the variation in speeds you get when not taking care to set the speeds right on the line.
I think this has been a very worthwhile project - simple, inexpensive, and as far as I can tell an accurate way of keeping tabs on shutters which have a habit of losing accuracy over time.
Re: Speed Graphic Focal Plane Shutter
This has been a very interesting thread... now you have me thinking about testing the shutter on my recently acquired Speed Graphic. Will have to take it to a mate who has a collection of oscilloscopes and see what happens.