Crown Graphic Special Top Rangefinder ??
First question: Would any Crown Graphic Top Rangefinder Camera, that was known to have been calibrated to a Schneider Xenar 135mm/4.7 lens, be automatically calibrated to another Schneider Xenar 135mm/4.7 lens that wasn't original to the camera?
Second question: Are these Graflex top rangefinders easy to calibrate to other brands of 135mm lenses?
Did some digging...I think I found my answer...The Top Rangefinders have cams, so if I understand it right, I can use any 135mm focal length lens as long as it has the 135mm cam...Correct?
Sorry, the cams are lens-specific, not focal length-specific. This because actual focal lengths of lenses of the same make, model, and engraved focal length will vary.
Here's a Zeiss example. I once bought 9 AGI F135 cameras, each with a pair of 38/4.5 Biogons, and a pair of 38/4.5 Biogons that had been held as spares. The F135 is fixed focus. Each lens was marked with its measured focal length. Design focal length is 38.5 mm, actuals ranged from 38.2 to 38.8. Each lens had a shim that sat between it and the camera's main casting to collimate the lens to infinity. Each shim was marked with its lens' serial number and its thickness, to 0.01 mm. There were many different shims. I don't think Schneider's quality control was more stringent than Zeiss'.
The TRF Crown Graphics use a cam. The only adjustments you can make to the RF are to change the cam and move the infinity stops. The cam that came with a camera that was originally fitted with a 135mm Xenar will certainly work with any other 135mm Xenar of similar vintage. It might or might not work with another make of 135mm lens. So, in practice, if you replace the original 135mm Xenar with a modern 135mm Sironar-N for example, the rangefinder will be off at either near or far distances - or both.
Thank you...Very helpful.
Originally Posted by Dan Fromm
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I was going to try a Nikkor-W 135mm on the camera. So if I leave the current cam in, I may have to adjust the infinity stops? Or is there more to it than that?
Originally Posted by BradS
As Dan said, lens vary in actual focal length from their marked focal length, all brands, all focal lengths.
Originally Posted by BradS
The list of Pacemaker Graphic Rangefinder cams is http://www.graflex.org/speed-graphic...nder-cams.html
The Graphic Rangefinder, found on Pacemaker Graphic cameras from 1955 onward, is calibrated to read infinity when the cam follower arm is .437 ▒ .001 inch from the cam base. This is the only adjustment of this rangefinder.
See: http://www.southbristolviews.com/pic...TRFService.pdf . A lens that is focused at infinity on the ground glass with the RF indicating infinity will be in focus at infinity but be out of focus at closer than infinity distances depending on the focal length difference between the lens and the focal length the cam was cut for. A 133mm lens used with a P31 cam will be off from the 15-25 feet range and closer and when used with a P5 cam it will be off at about 10 feet and closer.
Ok. Let me catch up...I have a Xenar 135mm lens, and I have a Top rangefinder Crown Graphic...They didn't start out in life together, but the camera did originally have another Xenar 135 with the right cam...If I marry these two together...No problem, right? But the Nikkor will not work with the rangefinder.
Originally Posted by shutterfinger
There's no guarantee that one 135/4.7 Xenar will have the same focal length as another. If the focal lengths differ the two lenses will need different RF cams and the bed stops will have to be positioned appropriately for the lens on the camera.
I have a Xenar 135mm lens, and I have a Top rangefinder Crown Graphic...They didn't start out in life together, but the camera did originally have another Xenar 135 with the right cam...If I marry these two together...No problem, right? But the Nikkor will not work with the rangefinder.
There's no guarantee that a randomly selected 135/5.6 Nikkor will have the same focal length as a randomly selected 135/4.7 Xenar. Same as above.
And there's no guarantee that a randomly selected 135 Nikkor with the same focal length as a randomly selected 135 Xenar will have the same flange-focal distance. If the focal lengths are identical the RF cam will be right for both lenses but the flange-focal distances aren't then the bed stops will have to positioned appropriately for the lens on the camera.
I'm sorry not to have given you the answer you want.
Take your Pacemaker, Crown or Speed Graphic, Install the cam in the rangefinder, and pull the front standard out to the infinity stops and lock. Focus the rangefinder on an infinity target at least 5000 feet away. Lock the rails with the focus lock lever. Install one of the lens you have and check the focus on the ground glass.
A. If the ground glass image is in focus, aperture wide open, then focus on closer objects with the rangefinder and check the focus on the ground glass. If the ground glass agrees with the rangefinder then the lens and cam match.
B. If the focus is off then fold the infinity stops down and reposition the front standard to where infinity is in focus and lock the front standard. A shorter focal length than the infinity stops setting will focus behind the existing infinity stops while a longer than the infinity stop setting will focus infinity further out on the bed.
With both the rangefinder and ground glass in focus focus on objects closer and note where the lens and rangefinder diverge.
Standard focusing distance markings are Infinity, 100 ft., 50 ft., 25 ft., 15 ft., 10ft., 8 ft., 7 ft., 6 ft.
You currently have the camera, cam and lens in question.
Only you can answer the question of whether your lens match the cam closely enough to use.
You have been told how to find out.