I have acquired a late Crown Graphic with a top-mounted rangefinder--but no lens or lensboard. How do I determine which which lens (and thereforefore which cam) it is set up for/with? Also, for extra credit, what battery model fits it little built-in focuspot lamp?
Thanks--I couldn't find a thread on the forum with the answer....

hey pinotgraves

go to http://graflex.org/speed-graphic/top-rangefinder-cams.html


I use AA

1banjo

Lens were optically measured and a cam was cut to match the actual focal of the lens. Actual focal length of a given lens may be ± 5% of the stated focal length.

With the cam and lens installed on the camera focus the lens on an infinity target at least 5000 feet away, then check the rangefinder for coincidence. Infinity position of the rails is fully in then out .040 inch ± .010 inch. With rails locked in this position the RF should be in coincidence with any cam installed. If the lens is not at infinity focus, loosen the infinity stops set screws and move the lens to where the infinity target is in sharp focus with the front standard locked and both sides equal distance from the rail ends. Slide the infinity stops up to touching the front standard and tighten the exposed set screws. Unlock the front standard, move it back and tighten the back set screws. Over tightening the set screws will damage the rails. Front set screw should have a flat bottom, rear set screw should have a sharp point.

With a matched lens/cam both will be in focus thorough the entire focal range, a close match will be off more at close distances than at far distances. All test should be done with the lens wide open.

Regarding the info shown in:
http://graflex.org/speed-graphic/top-rangefinder-cams.html , I see the following data for cams P32 through P38:

32 138.7
33 140.4
35 144
38 148.9

My SSG's lens board has "CAM 36005 P34" stamped on it. Does this mean its Optar/Rodenstock "135mm" lens' focal length is really between 140.4 and 144 mm? There's no P number "34" in that list.

Still learning........

Thanks,

Bart

The cam information for the Top Rangefinder Pacemaker does not apply to the Super Graphics.
The cam list for the Supers is:
http://graflex.org/speed-graphic/super-graphic-cams.html . (Be sure to leave a space after a pasted link as the system will include any character up to the next space as part of the link making the link bad.)

The P34 cam is machined for a lens having a focal length of approximately 136.4mm.

45PSS, thanks for noting my link to the wrong camera....and that the link included a character that must not be part of it. I'll save the correct link in my Graflex files.

Bart