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Possible to manufacture a Horseman 970 Rangefinder Cam?

loccdor

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For reference, this is what they look like:



I want to put a Nikon SW 90mm f/8 lens on a Horseman 970. This is not a standard lens for it so there are no cams made for it to couple the rangefinder.

Questions...

Can they be made DIY?
Does it have to be metal?
It seems the top surface has a curve that is what actually controls the behavior.
Or, should I just buy a 90mm cam meant for a different lens, because it will be "close enough"?
 
I would bet that a 90mm generic or for another lens would work fine. The issue will be setting the infinity or zero point as lens design can lead to different back focus distances, etc. I'd expect this to be a simple mater of setting the lens standard stop correctly. Then confirm focus at two or three closer distances.

I wonder if you traced the 105 and the 75, then ran a curve that split the middle, if you'd get the proper shape?
 
Thank you @Dan Daniel , that's helpful. This is the shape of the 90mm so it does look pretty close to what you said.

 
if you can figure out the correct curve of that “top” part, i can create a .DXF file for you. That would allow you to have the custom part laser cut out of metal. or we can make a 3D file and you can try printing it.

should be easy enough

if you wanna manufacture this, and need some help, shoot me a direct message
 
@ivan35mm Thanks. If someone comes along with this cam and is willing to scan it, that might be worth a try.
 
I scanned all mine and posted either here or large format form. I could re-post them.
 
ic-racer said:
I scanned all mine and posted either here or large format form. I could re-post them.
Click to expand...

That would be very helpful. I searched but did not find it.
 
yea, just need one solid measurement to scale everything. would also need the thickness of the metal.
 
I found a thread on photo.net: https://www.photo.net/forums/topic/492549-horseman-6x9-cams-for-120-and-90mm-lenses/



The person there is using 1mm aluminum to make them, but it seems the originals are closer to 1.5mm. They are also saying they are 4cm wide. Some images I measured online suggests they are more like 4.5cm. I have no idea how accurate this is. If someone could measure one of theirs with calipers it would really help out.
 
Last edited:
I’m away from home until the weekend, but if no one else steps up, I’ll try to remember to put some calipers on one of my cams.
 
I think I'll shell out the 50 bucks to buy the 90mm cam. Some of the others are over $150, so it could still be useful to manufacture a set of them (and a possible lucrative 3d printing opportunity, assuming there's a big enough market for these old horsemen). I'll post its measurements when I have it and maybe this will help someone else in their search.
 
The shape of the curve is most important. The height is somewhat inconsequential for most of the cams, as the infinity stops will be set individually for each cam/lens combination. The cams that share infinity stops, however, will need to be made with the exact height.
 
It all depends on the real focal length of the lens that the horseman cam was cut for and the real focal length of the lens you want to use. Unfortunately that data is missing, or at least I haven't found it. I modified a 65mm cam by carefully polishing it to track my 58mm Hexanon lens. It is time consuming and if you do to much you are cooked. I have also made a few from brass bar stock I bought on Amazon. You really have to be in love with these cameras to do it though. Good luck!
 
Zone focus scales too, for anyone that needs them. These, are for the Horseman FA.
 
Thank you! How thick are the cams?
 
I went to Harbor Freight and bought their version of a Dremel that was rechargeable and an additional kit that had a bunch of sander wheels, polishing wheels, and cutters. I used some fine valve lapping compound on the polishing wheel on its lowest setting and went to work. Testing it often until my ADHD kicked in (about 15 min.). Had a coffee break and started again. When I was done I relabled it and went for a shoot. It works. I bought some brass stock .032" x 3/4" x 12" 2 pieces from Amazon or Ebay, can't remember, and made a few cams from scratch for a few oddball lenses like my 127mm Ektar and my 162mm Swollensak. If you try making one for your longer lenses and you over do it, go for a shorter lens and you won't waste a blank.
With the 970 and 980 I would drill the lensboard hole offset about 14mm or the amount of maximum side shift and then you could have more rise, shift and drop.
 
@ags2mikon Thanks for the tips. Sounds like you've really enjoyed these cameras.
 
If the cams are laid on top of a piece of graph paper when being photographed, preferably on an aligned copy stand arrangement, all of the dimensions should be measurable.
Good luck with the project.
 
I received the 90mm cam: it's exactly 40mm in width, and approximately 1mm in thickness.
 
adobe illustrator is good for 2d vector files. like dan said, you can just trace it.

if you want to scan the 90mm cam, you are also more than welcome to send me the scan, and i’ll trace it in fusion 360, so that you have a 2D vector (.dxf) and 3d render (.stl)

if you wanna make these outta metal, use sendcutsend.com
 
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