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Rodenstock 138mm Float

med

Active member
Forgive me if this has been covered here or elsewhere, but how does the floating lens element work? Does it have its own ring with printed focus distance ranges on it, to manually optimize the correction, or is the floating element automatic with use of the helical? As an Arca user I don't know the Rodenstock helical look to know what is normal and what is different compared to other lenses, but based on the image it looks like there might be a ring behind the aperture mount that performs the correction manually?

If the floating element is automatic with use of the helical then I don't know where that leaves us Arca users with the integrated focusing helical...
 

dchew

Well-known member
Forgive me if this has been covered here or elsewhere, but how does the floating lens element work? Does it have its own ring with printed focus distance ranges on it, to manually optimize the correction, or is the floating element automatic with use of the helical? As an Arca user I don't know the Rodenstock helical look to know what is normal and what is different compared to other lenses, but based on the image it looks like there might be a ring behind the aperture mount that performs the correction manually?

If the floating element is automatic with use of the helical then I don't know where that leaves us Arca users with the integrated focusing helical...
The floating element is automatic, tied to the helical. I suspect it will work with the Arca helical by setting a "zero" point on the Arca helical, focus close using the lens helical, then fine tune with your Arca helical. That way, the float will be at the right setting, at least for all practical purposes. Actually, with this lens that process would be helpful for critical focusing.

Dave
 
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med

Active member
The floating element is automatic, tied to the helical. I suspect it will work with the Arca helical by setting a "zero" point on the Arca helical, focus close using the lens helical, then fine tune with your Arca helical. That way, the float will be at the right setting, at least for all practical purposes. Actually, with this lens that process would be helpful for critical focusing.

Dave
Gotcha, thanks. Yes, I suspect you are right. This will be a first for Arca R-mount I believe.
 
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