Identifying Crown Graphic RF cam focal length & setting up infinity stops

[Kevin Crisp]

If you search for Crown Graphics on that auction site, the 135mm f:4.7 Schneider does seem to be the most common lens for sale at the moment. Historically maybe it wasn't. My experience has been that the longer Raptars are fine, the 90mm ones however are hit or miss. I think with a little patience you ought to be able find just the 125 Xenar lens for sale.

On mine, I ditched the Xenar and put on a modern 135mm Symmar. Folds up fine inside the camera and with slight modification (well, I had somebody make me an adapter) the body release works with the Copal 0 shutter. And you will be able to use front rise if you want, which is quite a stretch with the limited coverage of the Xenar.

I'm not sure a 65mm lens will work on a Crown, but someone here must know that. I think with a 75mm the bed might be in the photo, there is a drop bed feature that gets the bed out of the way, the lens then goes up with front rise and tilts to square up with the film plane. But I don't know if it will work with a 65mm.

Again, my experience at least with the Kalart rangefinders is that you can go through the adjustment procedure (at least twice) and get much more accuracy that plus or minus a foot. I did one time have mine go out of calibration but that was years ago and it has stayed where it should since then.

[Alan Gales]

Just some information for you.

A Rodenstock Geronar 210mm f/6.8 lens or the Caltar version of the same lens will just fold up inside a Crown Graphic. It's a little longer than a 180 if you want something longer. I had a Crown with the 135 Schneider lens and the 210 Caltar. It was a nice pairing. I bought an extra set of infinity stops for the 210mm lens. I set them all the way out as far as I could. I seem to remember that there was a scale which I could have removed to set them perfectly but I just pulled the lens standard out to the infinity stops. I still had to focus ever so slightly with the focus knob but it was no big deal. Real fast to use.

For a 180 lens I would set the infinity stops using the ground glass like mentioned earlier.

[Dan Fromm]

Kevin, see post #5 above re w/a lenses on 4x5 Crowns.

However, since I use 2x3 Graphics I'm not sure which w/a lenses make infinity on a 4x5 Crown with the front standard exactly on the hinge. I'm sure there are some that do. Two solutions: give up some near focusing distance and put the standard at the very front of the inner rails or for working closer up give up some far focusing distance and put the standard as far back as possible on the outer rails and then. as you suggested, use back tilt and front rise to center the lens' optical axis on the gate.

[Neal Chaves]

65mm lens can work on the Crown. The bed is dropped and the infinity stops are placed on the inner tracks BEHIND the front standard. The camera will fold with a 65mm f8. Drop the stops and push front standard all the way in. This is a delightful camera to use. With roll film, the stock viewfinder with the WA optical mask (made for 90mm on 4X5) is very accurate. For 4X5 use a 20mm (for 35mm) finder on a shoe. You cannot use the frame finder because the front standard is now inside the body and you cannot pull it up.

[nonuniform]

Here are four TRF cams that I cut myself from hobby shop brass stock. Left to right top to bottom 210Attachment 155081mm, 90mm, 150mm and 65mm. These are far more accurate than factory cams. Note that the 210mm and the 150mm cams are "nosed off" for one close focus distance at which the camera can be used like a "Big Shot". Here's a "Big Shot" with the 210. TRF Graphic, Vivitar 285 with bounce card.Attachment 155082Attachment 155080

What thickness brass did you use? I guess I could just take my cam out and compare.

Did you start with a particular shape when making the cam and just grind it down manually until it focused across the distance range?

I keep meaning to create a cam for a couple of lenses. Would love to hear how other people do it.

[Neal Chaves]

If you have a pristine, untouched since factory new, RFsystem on the Crown it is possible to cut very accurate cams from the hobby shop brass stock. Choose stock the same thickness as the factory cam and just a bit wider. The height of the cam (the point where the follower makes contact) at infinity with track all the way back and hard against the stops in the body is .437 + or - .002". That point should be near the top of the cam, but not at the very end. Then it is just a case of "putting it in and taking it out" while you file away and check focus on the ground glass at a number of distances from infinity to close-up. Sometimes it comes down to just one or two passes of a fine file to get it just right. You can use factory cams of approximately the desired focal length to determine the general shape of the curve, and it is a curve not a straight line. All cams are the same length. You can use my photos above as a guide for 210, 150, 90 and 65mm lenses 135 and 127 will be slightly steeper than 150, 180 slightly less so. 75mm lenses are not really practical because they sit on the hinge of the track and prevent dropping of the bed.