Linhof Technika Rangfinder Cams

I recent bought a user Technika IV. It had no lens but came fitted with a 150mm rangefinder cam.

I am aware that Linhof advises that the camera and lens must be matched and the rangefinder cam custom ground for the specific pair.

Undaunted, I decided to see if I could calibrate the rangefinder for a 150mm Fujinon W that I had on hand. I was successful.

I brought the rangefinder and groundglass image into agreement at 9 feet, using a newspaper focus target and a 4x loupe to view the image. I brought the groundglass image into focus by sliding the front lens standard, very carefully, along the rails. It helps to use a feeler gauge between the front standard and a stop to judge motion.

Once this was done I checked agreement between the rangefinder and groundglass at 19 feet and 150 feet (It's winter here, the close targets were indoors and the distant one a greenhouse viewed trough a back window). The rangefinder and groundglass agreed exactly for the two more distant targets, to the extent of my ability to determine agreement, using the loupe. Done, I then set the stops.

I was also able this with a second, different, Fujinon 150W.

I conclude that I now have a lens/rangefinder combination in useable/useful calibration. They key point, to my mind, is that with the RF I can focus the lens as accurately at I can using a darkcloth and loupe on the groundglass.

Your mileage may vary, of course; hard to beat the price, though.

Good light all.

Good for you! As much as our esteemed Linhof former rep would advise, it is not always necessary to have a Linhof guru grind a cam to finesse match the RF. (although I'm super happy with three matched cam lenses... at a cost.)

Well necessity is the mother of invention.

Lenses of the same marked focal length can differ in actuality, even those of the same brand. It's possible to match up a mismatched cam for a new lens. Areas that are too high on the cam can be filed down, and areas that are to low can be stretched out by flattening on an anvil and later touched up wit the file.

I bought a cam from Shapeways a while back. Although I have yet to calibrate it and use it, here are the instructions from the designer.
Attachment 213244

That is great! Thanks.
I have also recently found this... https://christiannicolas.net/camming-2/

Pieter and Embdude: those are good resources, thank you for posting.

I recently sold two lenses here that I had Master Tech. Cams for but had forgotten all about them (I never use the Rangefinder). I have started to rethink this as my vision has been changing (not for the better). An accurate Rangefinder, I think, would be helpful in focusing an image in dim light - I never tried - just thinking out-loud.