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2x3 Graphic vs. Graflex film plane register

 
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john wilton



Joined: 26 Aug 2008
Posts: 26

PostPosted: Thu Mar 12, 2009 6:43 pm    Post subject: 2x3 Graphic vs. Graflex film plane register Reply with quote

Please forgive post as this must have been covered before, but I can't find it.

I am trying out a 2x3 RB Junior SLR, Graflex back, that came with a rollfilm back. The back is marked "23 GRAFLEX" across its back, but it is actually a Graphic back....it has the Graphic's raised light trap ridges, and the Graflex-type grooves and notches were clearly machined into it after it left the factory. A channel has been dug into the felt on the camera to receive the Graphic ridge.

My first roll has a focus issue...sharp focus in the negs is a bit behind where I focused on the groundglass. Aside form operator error and groundglass collimation error possibilities, I wonder if Graphic and Graflex holder film plane depth is spec'd differently.

Unfortunately I don't have any true Graflex holders to measure the depth of the film from the face of the holder. (The film pack adapter I have, but I don't know what thickness to allow for the film pack.)
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C. Henry



Joined: 13 Dec 2005
Posts: 360
Location: North East Georgia, USA

PostPosted: Fri Mar 13, 2009 6:19 pm    Post subject: Reply with quote

For what it is worth, I measured the following with a depth micrometer. All measurements are from the face that rests against the camera back to the surface behind the film on the unit measured.

2 1/4 x 3 1/4 Graphic Film Holder Type 5 -- 0.210"

2 1/4 x 3 1/4 Grafmatic Film Holder "23" Graphic (measured to septum in taking position) -- 0.211"

Singer Graflex RH8 Roll Holder (measured to pressure plate) -- 0.206"

Presumably the film and backing paper are not quite as thick as sheet film by about 0.004" - 0.005"

Hope that helps and that someone else can make similar measurements on the Graflex units for you.

C. Henry
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mopar_guy



Joined: 07 Aug 2008
Posts: 126
Location: Washington, the State

PostPosted: Sat Mar 14, 2009 2:36 am    Post subject: Reply with quote

Hi John,
I have a few Graflex Style 2x3 sheet film holders that are in like new condition in boxes. The range of measurements that I find is between 0.198 and 0.206 inch.
Regards,
Dave
_________________
I guess that I could get a digital camera but it would be obsolete in a couple of years (three tops). Or I could use my 3x4 Anniversary Speed Graphic. Heck, it's been obsolete for 50 years. That's way better than digital.
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DHF845



Joined: 20 Jul 2008
Posts: 103
Location: Hudson Valley Area, Upstate NY

PostPosted: Wed Mar 18, 2009 11:10 pm    Post subject: Graphic vs. Graflex film plane register Reply with quote

I have Graflex SLR's w/ Graflex roll holders, and Speed Graphics with Graflok backs using Graphic and Singer roll holders. I compared them and the film plane is consistent in all of them.
Perhaps felt light-trap on Graflex is introducing .5 mm of error? Have you checked the ground glass? If it was ever removed or loosened, it's out of register. Find a Graflex SLR rear ground glass panel and compare ground glass sharpness using a loupe. Chances are focus at film plane isn't same as focusing screen. The ground glass screen can be adjusted and shimmed into position.
One final possibility is the pin-roller problem. Early Graflex 23 roll holders c. late 1940's-early '50's had problems getting film flat (no pressure plate). Later lever wind backs and Singer backs added pin rollers at film plane which greatly improve things. The early Graflex 22 backs aren't as bad, the film doesn't seem to curl away from the plane as much.
I use several early knob-wibd Graflex 23 backs on my RB Series D and RB Series B. I always stop down, or I expect a little softness, which lends a pictorialist look to the photos, which is not always desirable.
_________________
Got first Speed Graphic at 15 (1976).Other kids were using 35mm SLR's. I ran around with flashbulbs and sheet-film holders, I wanted to be Weegee (#2084).
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Les



Joined: 09 May 2001
Posts: 2682
Location: Detroit, MI

PostPosted: Wed Mar 18, 2009 11:31 pm    Post subject: Reply with quote

Graflex always said there was a difference in the film plane register between Graflex backs and Graphic backs. Right now I can't put my finger on the data as to exactly what the difference was.

Les
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"In order to invent, you need a good imagination and a lot of junk" Thomas Edison
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