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View Full Version : Extra Stops on a Kalhart Crown Graphic



Frank Petronio
15-Oct-2010, 11:19
So I've had Crowns on-and-off for years, but always tried to get the top rangefinder models that use dedicated cams for each lens. With the Kalhart side-mounted rangefinder, my understanding is that it is calibrated for only one lens, usually the 135mm stock lens that usually comes with the camera.

So how come I see cameras set up with two sets of infinity stops and focusing scales? Are they used for scale focusing only?

And are the focusing scales marked somewhere to identify which lenses they are for? I mean a 90mm and 210mm are going to use vastly different focus scales, right? (Suddenly I am doubting myself but I don't have the gear at hand to check myself.)

Vick Vickery
15-Oct-2010, 11:23
Previous owner probably used more than one lens length and the extra stops got him started at infinity with each lens rather than just guessing at how far to pull out the front standard with the focusing rails all the way back.

rdenney
15-Oct-2010, 11:41
So I've had Crowns on-and-off for years, but always tried to get the top rangefinder models that use dedicated cams for each lens. With the Kalhart side-mounted rangefinder, my understanding is that it is calibrated for only one lens, usually the 135mm stock lens that usually comes with the camera.

So how come I see cameras set up with two sets of infinity stops and focusing scales? Are they used for scale focusing only?

And are the focusing scales marked somewhere to identify which lenses they are for? I mean a 90mm and 210mm are going to use vastly different focus scales, right? (Suddenly I am doubting myself but I don't have the gear at hand to check myself.)

Yes, they use different focus scales. For me, though, I put multiple stops just to reduce fiddliness--the lens never needs to be closer to the film than infinity focus. And then I can focus using the ground glass without having to readjust the front standard position.

My own trick, still in the middle of implementation, was to start with a top-rangefinder Speed Graphic and then add a Kalart on the side. My intention is to calibrate the Kalart for the 8-1/2" Paragon that I've tasked for that camera, and for which no cams were made. I have an accurate cam for the 127mm stock lens. I will also add a third set of stops (for convenience) for the 90mm W.A. Optar, and then make separate marks on the focus scale. The WA lens is easier to scale focus, of course. Probably a dumb idea, but I hope it works out.

Rick "waiting to finish a remodel project before finishing that camera project" Denney

Dan Fromm
15-Oct-2010, 11:42
When the stops are set up properly, the distance is measured using the RF and the focusing scale the RF is set up for. The front standard is put against the stops for the lens in use; this can be done before measuring the distance since all the RF knows is how far the rails have been moved from the "set up" infinity position. Then the standard is moved until the focusing scale for the lens in use is at the measured distance.

Similar messy and painful procedures are used to focus, e.g., Kodak Retina IIc and IIIc with the w/a or tele lens.

domaz
15-Oct-2010, 11:44
Focusing scales are marked on the back (have to take them off to see). It's some weird Graflex part number system. I'm having trouble finding the list that says which part numbers correspond to which lenses- but I found it one day after some searching.
I was disappointed that mine turned out to be a 127mm scale instead of a 135mm (the only 127mm lenses are press lenses!).

BetterSense
15-Oct-2010, 12:07
Have you tried it anyway?

I have a 127mm lens now, and my rangefinder is bang-on. I used a 135mm lens a bit in the past, and I didn't notice the rangefinder being off. Maybe 127 and 135 are close enough to each other that it doesn't matter?

Mic B
15-Oct-2010, 12:21
For calibrating the Kalart to whatever lens you wish to have on your Graflex, Mr. Jo Lommen (http://www.xs4all.nl/~lommen9/technical%20page/start.html)'s webpage might be helpful.
... just click on Adjusting and follow the instructions.


I wish all of you folks a nice weekend!

Mic

Neal Chaves
15-Oct-2010, 19:54
I have cut many cams for my TRF Graphics from 58mm to 250mm and 270mm telephoto. It's not very difficult and there is a piece of brass stock in the hobby stores that is just the right size. The nice thing about cutting all your own cams for the camera is that you can set them all up to "hard stops", exactly at infinity. With factory cams, some lenses may have to be set up on "soft stops". I would never use a factory cam again now that I have learned to cut my own. I have a couple of factory cams I'll put in the classifieds.

I have stops on the Toyo 810M field camera (no range finder) which make it easier to find infinity, especially with the short lens and the bed dropped, but I always set them up a bit "soft" so I can see and be sure of infinity focus.

I have the Crown and Speed repair manual on PDF. If anyone wants it e-mail me. It has the list of all cams and the focusing scales.

BradS
15-Oct-2010, 20:56
I think Dan has it. The Kalart is calibrated to one lens...and there is one set of focus scaless assoicated with each lens-infinity stop pair.


Let's assume that the kalart is calibrated to the stock 135mm lens, and that you have a 210mm lens mounted with a set of infinity stops and a distance scale calibrated for both lenses.

when the 210mm lens is in use, you focus the rangefinder, read the distance off the distance scale for the 135mm lens and then move the front standard (with the focus knob) so that the 210 is focused at that distance. In effect, you transfer the distance measured with your range finder to your focus.

make 'em sense?

IanG
16-Oct-2010, 00:20
There's little need to use the Infinity stops in pairs unless you rely totally on Range-finder focusing.

I use one for a 135mm lens and the other for a 90mm on my Crown Graphic. The Meyer Rangefinders set for a 150mm and unfortunately is not adjustable for a different FL.

Ian

rfesk
17-Oct-2010, 11:31
I use a Busch Pressman with the Kalart on the side. Over the years have purchaed two more stops (I call them infinity stops - set to infinity of the lenses I use most.)

The idea is to set the Kalart and distance scales for the lens used the most (my 135 Rodenstock) and have scales made for the other two lenses.

So, in practice, focus using the Kalart (which had been adjusted for the 135 mm Rodenstock), read off the distance determined and then set that distance on another scale dedicated to one of the other lenses that is in use.

The scales that I use for the other lenses are custom made by me.

tbeaman
20-Oct-2010, 20:40
When the stops are set up properly, the distance is measured using the RF and the focusing scale the RF is set up for. The front standard is put against the stops for the lens in use; this can be done before measuring the distance since all the RF knows is how far the rails have been moved from the "set up" infinity position. Then the standard is moved until the focusing scale for the lens in use is at the measured distance.


I think Dan has it. The Kalart is calibrated to one lens...and there is one set of focus scaless assoicated with each lens-infinity stop pair.

Let's assume that the kalart is calibrated to the stock 135mm lens, and that you have a 210mm lens mounted with a set of infinity stops and a distance scale calibrated for both lenses.

when the 210mm lens is in use, you focus the rangefinder, read the distance off the distance scale for the 135mm lens and then move the front standard (with the focus knob) so that the 210 is focused at that distance. In effect, you transfer the distance measured with your range finder to your focus.



The idea is to set the Kalart and distance scales for the lens used the most (my 135 Rodenstock) and have scales made for the other two lenses.

So, in practice, focus using the Kalart (which had been adjusted for the 135 mm Rodenstock), read off the distance determined and then set that distance on another scale dedicated to one of the other lenses that is in use.


Well, now. That's just smart. Thanks for that, folks.

Now I need some extra infinity stops. Wish they didn't cost so much.