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Super Graphic lens and RF limits

 
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richydicky



Joined: 07 May 2017
Posts: 3
Location: UK

PostPosted: Tue Aug 15, 2017 9:55 pm    Post subject: Super Graphic lens and RF limits Reply with quote

I've got a Super Graphic and recently obtained a Kodak Ektar 203mm lens. The infinity stop for this is about 3mm from the end of the rail so it would be impossible to install stops so I just carefully set it to marked points. I also fabricated a temporary rangefinder cam which works well enough though the shortest focus distance limit, the end of the metal RF tape range, is about 8 foot.

But this made me think about how longer lenses are supposed to be accommodated seeing that the 203mm infinity setting is near the limit of the rails and I can't set stops. Graflex made a 270mm for the Super and offered RF cams for longer lenses, so how does it work with these?

Richard
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Dan Fromm



Joined: 14 May 2001
Posts: 2020
Location: New Jersey

PostPosted: Wed Aug 16, 2017 12:05 pm    Post subject: Reply with quote

Something's wrong. According to http://graflex.org/speed-graphic/super-graphic.html the Super Graphic's maximum extension is 12 1/2". A 203 Ektar's flange-to-film distance at infinity is approximately 8". How did you find the lens' infinity position?

The longest lens Graflex offered for Pacemaker Graphics and the Supers is a 17"/5.6 Wollensak. It is a telephoto lens, its flange-to-film distance and back focus are much shorter than its focal length.
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richydicky



Joined: 07 May 2017
Posts: 3
Location: UK

PostPosted: Wed Aug 16, 2017 6:45 pm    Post subject: Reply with quote

Thanks for the reply. Yes, the figures all fit. To set infinity for a lens I rack the rails fully back (I prefer that rather than the Graflex recommended slight forward rail shift) then using the ground glass pull the standard out to focus at a point a few miles away. For the 203 Ektar that 8.5" flange plane distance matches the racked back rail distance to film plane, save a few millimetres.

The maximum extension is indeed 12.5" but I would not be able to set a lens of greater focal length than the 203mm Ektar without racking the rails away from the back stop stop to begin with to set infinity which would also negate the use of the rangefinder because you need that fixed infinity setting of the rails no matter what the focal length.
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45PSS



Joined: 28 Sep 2001
Posts: 3672
Location: Mid Peninsula, Ca.

PostPosted: Wed Aug 16, 2017 7:09 pm    Post subject: Reply with quote

Did you know the difference between a Super Graphic and a Super Speed Graphic is the label and the shutter the lens is in?
Have you seen https://graflex.org/helpboard/viewtopic.php?t=4653 and https://graflex.org/helpboard/viewtopic.php?t=4647

It is possible to modify the rangefinder actuator with a sleeve that will hold a 1/8 inch brass rod then cut the rod to length so that the rangefinder is at infinity with the rails at any distance from fully retracted. The rod has to be removed to close the bed. Cut one rod for fully retracted and one for the extended distance.
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