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Leitz BELUN 1:1 copy stand


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Hello Forum members,

I am hoping to get some information about the Leitz BELUN 1:1 copy stand for the Leitz Elmar 5 cm lens in combination with a macro-tube. The BELUN set that I just received contains the three rods imprinted "ELMAR" and a macro (extension) tube imprinted "ELMAR SUMMAR 1:1". I have seen photos of similar setups a couple of times online so I thought it should work for 1:1 reproduction (I want to digitize film using a SONY A7"). Testing the setup yesterday with my SONY A7 + KF Concept E - M-mount adapter + M-mount - LTM adapter + BELUN macro tube + Elmar 5cm lens + 3-leg copy stand setup, I wasn't able to achieve any in-focus image with the Elmar lens in any focussing position and aperture f/9. I only get grain resolution (or sufficient sharp images) if I push the Elmar halfway in. My question is now if there are any variations  in the setup or settings required? 

Any tips or info is very welcome.

Cheers,

 

Gabor

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1st verification, of course, to be made on the lens on Sony with adapter(s) - no BELUN : is focus OK with lens set at infinity ?

2nd : is the BELUN set mounted correctly ?

Possible issue to address... the male LTM thread of the 1:1 tube... it is made to engage onto a LTM body - see picture : how is your M-to-LTM adapter ? I mean that it could be that the depth of its female thread is someway shorter than the thread of a LTM body, onto which the repro tube must be screwed into completely... personally, I have some device with a female LTM thread that is like this.... and the final effect would be (for few millimiters, though) the same you quote... the set is "too long" -> retract a bit the Elmar...

Other (remote) chance : full mismatch between legs and tube : BELUN had a similar "brother" (BEINS) for Elmar 3,5 cm - shorter rods -. different tube, always for 1:1 .. of course, an Elmar-Summar tube - Elmar 5 cm mounted - wtih the legs for the Elmar 3,5cm would result in complete misfocus. (but opposite to what you observe : one had to advance the Elmar lens group towards the target, to achieve focus) 

Edited by luigi bertolotti
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Thank you very much for your helpful tips! I checked infinity (kind of because it is cloudy and night already here in Japan and no stars or moon visible) using two different Elmar 5cm lenses, a Summar, and a 50mm Summicron v4 (with the tab). All looked OK to me but I will have to check again using the moon or some bright stars. 

Closer inspection of the extender tube showed a small set screw and the inside of the tube has a thread. It turns out that it is length adjustable. After removing the set screw, I could shorten the tube and almost achieve perfect focus. I need to check with a piece of film again to focus onto the grain. Unfortunately, the set-screw allows only for one fixed length, might be for a short 5 cm lens. 

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Interesting finding... the set screw maybe is made to adjust for the exact focal length of the lens to use (Elmar and Summar, as many other lenses, do have variations around the nominal FL... it's identified by  a number engraved on the back of the focusing knob small arm) 

 

Edited by luigi bertolotti
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I saw it once, will check! I was thinking about the differences in physical length of the lenses. Since the lens is fixed at the front ring, this plays an important role. As I remember there a at least two different versions of the 5 cm Elmar, one called "kurz". Perhaps the length adjustment was designed having this in mind?

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23 minutes ago, maddoc2003jp said:

I saw it once, will check! I was thinking about the differences in physical length of the lenses. Since the lens is fixed at the front ring, this plays an important role. As I remember there a at least two different versions of the 5 cm Elmar, one called "kurz". Perhaps the length adjustment was designed having this in mind?

Maybe... is your Elmar a very old one or rather recent, say postwar ? 

But.. reasoning on the matter... the length of the (extended) barrel in itself ought not to cause issues ; on the contrary, to achieve an EFFECTIVE 1:1 repro ratio... the real focal length of the lens enters in the computation (i.e. fine adjustment) of the extension tube's length (if my reasoning is right... 🙄)

Edited by luigi bertolotti
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Here are, for possible use, two photos of the BELUN from my former colledction. I also had the version for Summar, the BESUM.

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