Correct!Originally Posted by Oren Grad
Rodenstock makes 23 different Helical Focusing Mounts for their lenses in 0 shutter. One of which is the 65mm Grandagon N 4.5.
These mounts are available for purchase for the user to mount their lens to it or the lens and fiocus mount can be ordered as a complete system.
In no case would the lens and focus mount be anywhere near $900.00 retail new. That would be the focus mount only. All 23 mounts are the same price.
I'm just setting the parts aside until I can send it in one trip to them. With my 65mm SA, I went the other way. I found a forum member keeping his lens but selling an unwanted helical mount, then I bought an identical lens/shutter as he had on it. Still looking for a 90mm combo together or find a helical mount that I can identify so I know which 90mm lens/shutter combo to mate to it.
I take it the chinese helical mounts rotate the lens whilst focussing....I gather the Schneider or Rodenstock ones don't do that (?) - I'd be rather annoyed to have the cable-release fly about, or have trouble reading the shutter speed, or aperture afterwards....
(So, when I recently made myself a small cheap W.A. 6x9 P&S using a 58mm Omegaron and a Mamiya-Press back, I just used the helix from an old Vivitar focussing TC. Cost for the TC was €2 by the way and an extra 20 mins of work....of course no comparison to that lovely Silvestri.....)
http://www.jeffbridges.com/perception.html "Whether you think you can, or think you can't, you are right."
The chinese ones don't rotate - they're a bit crude but adequate. The newer Fotoman mounts are very nicely made.
You might be able to adapt this: http://www.ebay.com/itm/ws/eBayISAPI...E:B:SS:US:1123
They are ill discoverers that think there is no land, when they can see nothing but sea.
-Francis Bacon
Finally my 65mm Schneider Helical mount arrived in a sealed box from B&H, but without any instructions. It's very well machined and the rotation of the focus is smooth like a classic Zeiss lens with just enough resistance. Rotation is through 270 degrees plus perhaps 5 degrees more at either end. Markings are in meters and ft with DOF indicated according to F stop. There's a removable lens mounting ring with 3 notches in the front and then, provided loose, a smaller 3-notched ring with a gasket. This adapter is for the lens that comes with my globuscope. The unusual lens is in a Copal 0 shutter and separated from a fixed rear leans locked in the camera body. A push pull sticky sliding mechanism is used for focus. I'll post pictures shortly of the helical adapter.!
Asher
So here are the pictures of the Schneider helical focus for its 65mm lens.
I hope this will be helpful enough for others. I've included a cm ruler to give you a reference.
Asher
As long as people were talking of mounting helical focusing mounts on Globuscope bodies, I thought I should post pics of mine. This is a 65 F8 S-A in a Schneider mount. With this lens and mount on the Globuscope body, the ffd is within 0.010 of the spec; thus no shimming was required, and all needed adjustments could be accomplished within the mount itself (this adjusts just like the Fotoman helical, and excellent directions for that exist).
I had to slightly bore out the throat of the body and sand that surface as flat as possible. Three 3-48 SHCS's come from inside the body and thread into tapped holes in the helical mount flange. I welded a small 304 SS tab onto the bottom of the body so that I'd have a strong hardpoint onto which to atach an Arca-style QR plate. Next it needs a finder and a decent GG.
They are ill discoverers that think there is no land, when they can see nothing but sea.
-Francis Bacon
John,
Did you tap the holes in the helical mount flange? The bolts would seem to me rather bulky. My helical focus has been fitted and I'll have to find out if they did the same. I like the two Arca Swiss tripod mounts. I found using an L bracket from Really Right Stuff almost fit perfectly to do the same and provide a hand grip. your method is neat. Good thing you welded the extra SS tab at the base as that seemingly strong looking circular "tripod mount" is actually riveted on to the thin expanded SS Globuscope body and is just intended to hold a spirit level underneath the camera!!
Are you going for a Maxwell screen? As this runs about $400, I'm considering adding a Graflok back, so that I can use rollfilm 6x6 to 6x12 or my stitch adapter for Canon DSLR's. The Maxwell Screen will be removable with the view box part of the Graflok back, so that I have the benefit of that screen for my 4x5 Crown Graphic with longer lenses. Hopefull, I won't have added too much weight.
Asher
I had originally drilled the holes in the helical flange to accept 2-56 screws, so the only option for a threaded hole was to go up to 3-48. The SHCS heads on the inside are bulky but that was the only option other than drilling another set of holes, which would be unsightly. The turned aluminum "tripod" support on the bottom isn't even as good as riveted on, it's held in place with a LH threaded stud so it can come loose unless you locktite it. The SS tab is spot-welded on (anything else would have deformed the this sheetmetal) so it took no skill. I then used a small 4-40 FHCS to connect the SS tab to the "tripod" mount so everything is structurally tied together.
How were you planning to mount a Graflok back? I haven't checked but it appears that there wouldn't be room for the bulkier Graflok back. I have a Sinar 6x12 panoramic back that slips under the GG, so that's what I'll likely use. Thanks for the questions.
They are ill discoverers that think there is no land, when they can see nothing but sea.
-Francis Bacon
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