Off-the-Shelf Top RF Cam Matches for Modern Lenses

[Frank Petronio]

RE: Top Mounted Rangefinder Cams on late Crown Graphics

To be specific, I'm wondering if anyone knows from experience if a modern 135mm Rodenstock Sironar will match up with which off the shelf Graflex cam?

If we compiled a table of cams that matched modern lens I bet a lot of people would find it useful. I'd compile it if people want to send me their experiental data. Thanks

[Frank Petronio]

I found that I have a P6 cam - has anyone had any luck using a 135 Sironar or Symmar with that particular cam? (I have a body and cam, no lens, so I need to buy a lens and rather get a newer one)

[tim atherton]

Frank, if you know the actual (as opposed to nominal) focal length of the lens can't you match it to the nearest graphic cam? (sometimes there is an exact match, sometimes it's a choice of a mm or two one way or the other) - I've found that's close enough for government work...

I've had super graphic cams that had also obviously been adjusted by a small stamp in the metal just behind the edge to push it out and add a touch to the curve - presumably done in conjunction with the actual lens and an optical bench though

[Frank Petronio]

Yeah, but I am L-A-Z-Y...

[Bill_1856]

Each cam was made for a particular actual focal length, not just the nominal FL. Close enough ain't good enough.

[paulr]

were the cams calibrated to individual lenses? i wonder, because sample-to-sample consistency of actual focal length has always been way off.

[Bill_1856]

Individual cams were matched to measured acutal focal lengths (plus/minus 1mm). See www.Graflex.org and search for "cams."

[Frank Petronio]

So, for a lazy guy like me, this means sending camera, cam, and lens off to Fred Lustig for him to measure the actual focal length of my particular individual 135mm lens?

And that between samples of a Sironar-N there will be a mm or two variation in focal length in random samples?

Thanks, not what I expected. Guess I'll go to a side RF instead! At least that I might be able to adjust...

[Paddy Quinn]

most of the cams were made to the standard focal lengths used with the particular model + some variations.

Unless it was bought new as a set (when the cam and lens were matched), you were supposed to send the camera + lens in to a service center where the actual focal length of the lens was measured on an optical bench and then the appropriate cam chosen. However, there were some gaps in the range of cams so sometimes the cam had to be modified, but there were limitations to this and they weren't usually ground and adjusted in the same way that linhof cams are. Sometimes the fit of cam to lens was "more approximate than others" as one old service tech once told me. Usually it was a pretty good match, but it isn't the most precision of rangefinder mechanisms anyway. The techs were pretty good at some skilful ways of adjusting cam and mechanism and making up for this.

Thats said, I've used a 151mm cam on a nominal 150mm lens and a 209.5 on a nominal 210mm lens and a factory matched 127mm cam with a 127mm lens and they are all close enough and work just fine

[Bill_1856]

Frank, do you actually have a top RF camera, or is this all just master...er, fantisizing?