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Schneider Xenar 4.7/135mm cam
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jpowersphoto
Joined: 04 Jun 2014
Posts: 3
PostPosted: Sat Jun 07, 2014 3:26 am   Post subject: Schneider Xenar 4.7/135mm cam

Hi everyone,

I have a cam from a super speed graphic that is a p-34 (136.4mm). I have a Schneider Xenar 4.7/135mm lens on the way. Can I use this cam with the Schneider Xenar 4.7/135mm lens?
45PSS
Joined: 28 Sep 2001
Posts: 4081
PostPosted: Sat Jun 07, 2014 7:21 pm

Lens are rarely their labeled focal length. They are a tenth of a millimeter to 3 or 4 millimeters either side of the labeled focal length.
The list of cams for the Super Graphic are here:
http://graflex.org/speed-graphic/super-graphic-cams.html
The greater the error between the focal length of the lens and the cam the greater the focus distance error starting at the closest focusing distance and going toward infinity.
A true 135mm with a 136.4 cam will experience a focus error of a few inches starting around 10 foot focus distance and closer. A 138.6mm lens with a 133.5 cam will experience a focusing error starting around 25 feet and be off a foot or so at 8 feet.

You will have to ask your lens and cam to find out if they are acceptability compatible.

Related posts:
http://graflex.org/helpboard/viewtopic.php?t=4653
http://graflex.org/helpboard/viewtopic.php?t=4647

The difference between a Super Graphic and a Super Speed Graphic is the label on the lip of the bed and the lens/shutter combination they shipped with when new.
jpowersphoto
Joined: 04 Jun 2014
Posts: 3
PostPosted: Sun Jun 08, 2014 7:37 pm   Post subject: Lenses & cams

Thank You so much for the quick reply and information!
:D
45PSS
Joined: 28 Sep 2001
Posts: 4081
PostPosted: Mon Jun 09, 2014 2:12 am

Once you get the lens check that the infinity stops and rangefinder are in sync.
Factory standard is:
Run the rails all the way in then forward .040 ± .010 and lock.
Install a cam in the rangefinder.
Mount the camera on a sturdy tripod.
Point the camera at an infinity target at least 5000 feet away. (a closer target will result in celestial objects being out of focus to soft focused at camera infinity with the lens wide open.)
With the lens wide open, unlock the front standard and slide it out until the image on the ground glass is sharp using a loupe.
Lock the front standard then check it for equidistant on each side from the end of the rails.
Adjust as needed until the front standard is square to the rails and the infinity target is in sharp focus on the ground glass.
Slide the infinity stops up against the front standard and secure in place with the front screw of the infinity stop.
Check the rangefinder for infinity focus. Loosen the RF actuator screw(s) at the left rear of the bed and adjust the actuator until the RF indicates infinity in the RF window then secure the position with the screw(s).
Over tightening the infinity stop screws will distort the rails.
The RF actuator has a tendency to shift inward toward the rails if set with the play toward the bed outside edge.
The flash calculator distance scale should indicate infinity but it does not affect the optical alignment of the camera if it does not.

The focus error estimates in my previous post are based on the lens and RF infinity setting to be in sync.
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