Diameter of Schneider Digitar helical mount, 47mm

[bglick]

Does anyone know the diameter of the Schneider helical mount that will fit the Digitar 47mm fl lens? I am hoping it's not much wider than the copal 0 shutter? No reference on the Schneider site for this specification.
TYIA

[Bob Salomon]

Rodenstock helicals for 0 shutters fit a 3 size hole. Schneider's should not be any different.

[bglick]

Fit a 3 size hole? Maybe my question was not clear.....
I am trying to mount two digitars, side by side, (stereo) both with helical mounts, I want the lens centers to be 66mm apart, in which case, the max. diameter of the helical focus mount can not exceed 65mm.

In the event I use the Rodenstock 60mm digitals, what is the max. diameter of their helical mounts?

TYIA

[Bob Salomon]

Bill, all of the Rodenstock helicals fit a 3 size hole. Their diameters are larger then a 3 size hole.

[Oren Grad]

Bill, the diameter of the hole required for a Copal 3 is 65mm. It sounds as though this isn't going to work for you.

[bglick]

Bob S wrote.... Their diameters are larger then a 3 size hole.

I did know this much!

Hopefully, there is someone on this forum who has good knowledge and/or access to the Rodenstock lenses / mounts in question. Oh yeah, Schneider too.....

Thanks Bob.

[bglick]

Oren, thanks for the response.....

If it's going to work, it will be very close. From pictures I have seen, the helical mount is only slightly larger than the diam of the Copal 0 shutter, which measures 61mm, not counting its hardware, which is OK, as I can mount their "empty" areas towards each other. So, I am hoping the helical mount is no more than 4 mm wider than the Copal 0 shutter, or 65mm.

I assume the helical mount for the digitar 47 is the same one used for the Super Angulon 47, right? TYIA.

[JimL]

I have a Schneider mount for a 75mm lens, which requires a mounting hole of 66mm. The maximum diameter is 71mm, which is right at the mounting flange. If all mounts use the same mounting hole size, they'll have approximately this maximum diameter.

Jim

[bglick]

Looks like I am at a dead end..... i.e. to maintain the desired 66mm lens spacing, I could try manual focus 5x7 camera, but with 47mm lenses???.... I doubt any 5x7 can focus at infinity with 47mm lenses. I needed the 5x7 for the 6x17 back insert for dual images....

Any brainstorms? I think Ebony makes a 4x5 that foucusses down to 47 mm without a recess lens board. I can NOT use recess lens board with dual lenses. With this, I may be able to use the Linhof 120 back, a true 120mm long. But their cameras take Linhof - type boards? I assume this is Linhof field boards? I doubt two 47mm digitars will fit on the board, and be able to insert the board into the camera? Arggggggg........

[Oren Grad]

You might call Peter Gowland and see whether he can built you a custom 5x7 architectural-type camera with a really thin box and a lens panel wide enough to accept two drillings.

Or, get a 5x7 back from Gowland, then see if SK Grimes can fabricate a box like that for you.

If you're thinking of using the Canham 6x17 back, you'll need a Graflok-style 5x7 back - maybe he'll be willing to sell you just the back, and you can ask SK Grimes about building the rest of a box camera around it.

Bear in mind that you'll also need some sort of septum inside the camera to keep the stereo images clean and separate on the film.

[bglick]

Oren.... Peter Gowland will not customize anything, he is trying to unload inventory only. I can't blame him, he is a legend, amazing career. I asked once long ago on different project.

As for you concept of a graflock 5x7 back to hold the film holder (and possibly ground glass) I was thinking the same thing.... but I still need to focus, and that would require a focussable lens box that bolts on the front of the 5x7 frame. Focus is NOT an easy task, hence why I was pursuing the helical mount focus. The young gent that took over Grimes since Steves passing....well, he is NOT Steve, he will be missed greatly.

Heck, I just ran some math, I may have over looked the obvious. It seems this should be a fixed focus camera......as my focus points will be from 24 ft to infinty. This being the case, it seems that lens would only move from 47mm at infinity, out to 47.3 mm at 24 ft focus. If I am right, a .3mm focus range is hard to acheive accurately, even with the best geared cameras.... if this is the case, I will just bolt the lenses to the frame at a compromise, say 47.2mm....I can test this till I get it right, then put some locktite on the adjustment screws, and keep it there for life. Does this make sense? I might be missing something?

If I am right, would you agree it would be best to see if Kieth will sell a 5x7 frame from the MCQ since I can be more assured of the gg / film alignment with his 6x17 back?

Is there a decent 47mm viewfinder being sold? This would be faster candids.

Thanks for your willingness to help.

[Oren Grad]

OK, I can't blame Peter either. He's done custom stuff for me in prior years, but he must be about 426 years old by now, about time to slow down a bit...

The benefit of getting Keith Canham's back isn't so much the gg alignment, it's that you need the Graflok-style sliders to be able to use his 6x17 rollholder, at least you do if you want to be able to swap with a gg for focusing. Walker in the UK and I think Tachihara in Japan are now also making backs with the necessary sliders, but standard 5x7 backs don't have them. Easiest thing is just to call Keith, tell him what you're trying to do, and see what he advises.

Afraid I'm not much of a viewfinder expert. I know there are lots of viewfinders and masks floating around, some of them frightfully expensive. Which one is best and/or most economical depends in part on what format you're using for the individual frames. If it's 6x9, you can often get away with one of the inexpensive Cosina/Voigtlander finders intended for 35mm cameras. But from your dimensions it sounds like you're probably looking at 6x6, which usually means a mask for one of the expensive finder systems like those for the Cambo Wide or Alpa 12 cameras. I don't know whether there are any old-time finders for 47mm on 120 that you could have adapted with a custom-made mask - I think maybe the Brooks Veriwide was supplied with a 47 SA. Maybe someone can figure out how to mask a C/V 21mm finder to square?

[Jim Rice]

As I recall the Brooks Veriwide used a Leica 21mm finder in conjunction with the 47 SA and 6x9 format. I never owned one, but I lusted after one for some time. IMHO the leading current choice would be the CV 21 finder, perhaps with some sort of external (front mounted) mask depending upon format. There was also the Graflx XL (SW?) version who's finder I have no idea about.

[Bob Salomon]

The Rodenstock Helicoids for view camera lenses are 70mm max. diameter.