I see lots of lenses fitted with helical focussing systems. Obviously these lens es are suited for non bellows type cameras. I am interested in knowing, who mak es the helical focussing systems? I assume only the manufacturer of the lens... and also, can a helical focussing system be used with any fl lens, or only lens es up to a maximum focal length? I never see them on long fl lenses?
Bill, I have a helical focusing mount for designed for (and made by) schneider 150mm apo symmar which I will be using for rodenstock sironar-N 150 mm with my cambo wide camera. Different lens manufacturer have different flange focal distance so if your camera has a fixed distance from your lens panel (ie non-bellows)then you'll have to make some adjustments. Which I will be doing when I receive my sironar-N 150mm lens soon.
Renee
Rodenstock makes helical mounts ($380.00 list) for their lenses in either 0 or 1 shutter.
Bob, is this the determining factor for helical mounts? Will Rodenstock helical mounts work on Schneider, Nikor, Fuji Copal 0,1 shutters? Are the helical mounts designed specificaly for one manufacturer? Since the Helical adds glass, any loss in image quality vs. bellows foccussing with non helical lenses?
There is no glass in a helical focus mount. Both Rodenstock and Schneider make helical focusing mounts for most of their wide angle lenses and some lenses up to 150mm. There are many mounts available. They are specific to focal length and come with the appropriate focus distance scale.
Bill. A helical focussing mount is just a threaded tube inside a double-threaded collar, inside another threaded tube. The threads are opposite handed, and when the collar is turned, the two threads wind the assmebly out or in to focus the lens, exactly the same as on a 35mm, or MF SLR camera. No optical components are involved.These mounts become impractical for very long focal length lenses, simply because of the extension involved, and the leverage of a heavy lens on the threads.
The old Mamiya Universl (1960's-'80's) system basically used small view camera type lenses (Very excellent Tessars) in helical mount to interchange on the same camera body. The Polaroid 600SE being the final version. All of the shutters were Seikosha 0. The 90 and 100mm 3.5 that was the normal for the system are sometimes VERY cheap on ebay and would provide a size 0 helical mount and a useable Seiko shutter if you're in the mood to tinker. The 127 4.7 that the 600SE used will cover 4X5 about the same as a Kodak Ektar of the same length. Just throwing out ideas so I won't be the only guy straying off into weird areas.
Jim, are you suggesting that any helical focussing mount can be used in any lens that used the same shutter? If so, this opens up a lot of possiblilities...
"are you suggesting that any helical focussing mount can be used in any lens that used the same shutter? If so, this opens up a lot of possiblilities... "
Of course not there is a tremendous difference in flange focal length between a 35mm Apo Grandagon and a 150mm Apo Sironar S or N all of which are in 0 shutter.
Then there is the matter of the DOF scale on these mounts. Again the difference is dramatic.
Then there is the difference in the distance scales. Infinity comes much sooner for a 35mm focal length.
Bill stop complicating things.
Each focal length lens that fits a helical mount has it's own helicoid.
Each has a dedicated DOF scale and focus scale. Each is at infinity when fully collapsed.
The most common helicoids where a single focus mount fits a wide range of focal lengths is the one for lenses in 39mm or 32mm enlarging lens mounts. These do not have scale, DOF indicators, etc. They do have extension tubes to allow infinity focus with longer length lenses or to extend maginfication.
They can not be used with shutter mounted lenses.
Every current Rodenstock brochure for large format lenses in 0 or 1 shutter includes a section on the helical focus mounts for them. Rodenstock also has a special brochure for enlarging lenses used for macro or CCD work in the Macro Focusing Mount.
Would you like these mailed to you?
Bill, No, I was suggesting that someone that wants to tinker on a budget might start with one of those. I think you'd be married to the Seiko shutter though, a copal probably wouldn't fit. You'd end up with adapted old, not pretty new, but all a helical mount does is move lens glass forward and backward the same as a bellows.
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