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retnull
4-Oct-2012, 09:38
Question re: Kalart rangefinder on the Graflex Speed Graphic:
If the rangefinder is calibrated to a lens of a specific focal length (say, 150mm) --
will the rangefinder still be accurate if a different lens of the same focal length is used?

Thanks,
Kurt

E. von Hoegh
4-Oct-2012, 09:45
Question re: Kalart rangefinder on the Graflex Speed Graphic:
If the rangefinder is calibrated to a lens of a specific focal length (say, 150mm) --
will the rangefinder still be accurate if a different lens of the same focal length is used?

Thanks,
Kurt

Maybe. Probably not. 150mm lenses are 150mm plus or minus say 5%. Then there's the flange focal length to consider.

rdenney
4-Oct-2012, 09:57
Question re: Kalart rangefinder on the Graflex Speed Graphic:
If the rangefinder is calibrated to a lens of a specific focal length (say, 150mm) --
will the rangefinder still be accurate if a different lens of the same focal length is used?

Thanks,
Kurt

The flange focal distance, which is the distance from the mounting surface of the lens board to the film when focused at infinity, is not the same thing as the focal length, and it varies.

And as the inimitable Herr Doktor von Hoegh said, the focal length on the lens is nominal, not exact.

You might get lucky. But if you are considering upgrading an existing 150 with a new one, then just recalibrate the Kalart for the new lens. It will only require slight adjustment. The instructions for doing so are here:

http://graflex.org/speed-graphic/kalart-manual.html

It's fiddly, but if you approach it with a sense of precision and devotion to following instructions exactly, it's doable by just about anyone.

Rick "who has done it for lenses outside the official Kalart range" Denney

E. von Hoegh
4-Oct-2012, 10:46
Inimitable! Vielen danke! Aber, "Herr Doktor" ist nicht korrect.

Ivan J. Eberle
4-Oct-2012, 11:22
I got rid of a Super Graphic I thought I'd use with a 135mm Sironar-N for this very reason-- e.g. not all 135mms are the same focal length. It was perfectly accurate with a 135mm Raptar, and moving the infinity stops alone didn't work.To my mind, the adjustable Kalart is preferable over the cammed top RF versions if you don't want to make your own cams for lenses that simply did not exist back when Graflex was yet offering them as new and need to use one.

Be aware that adjusting a Kalart is an iterative process that can be frustrating; it can take several iterations of the process until it's dialed in.