RE: Leica-R-Objektive auf A-Bajonett adaptieren

#1 von matthiaspaul , 20.03.2009 01:08

Liebe Mitglieder,

immer wieder hört man den Wunsch, Leica-Objektive mit R-Bajonett an Gehäusen mit Minolta-/Sony-A-Bajonett zu verwenden. Aufgrund des knappen Unterschieds der Auflagemaße (R-Bajonett: 47,00mm, A-Bajonett: 44,50mm) von nur 2,50mm gibt es bisher keinen kommerziell verfügbaren Adapter, der die Unendlichkeitseinstellung aufrechterhält. Aber inzwischen gibt es Bastellösungen, bei denen der Bajonettflansch des R-Objektivs entfernt und dafür der eines A-Bajonett-Objektivs montiert wird.

Von diesen konkreten Objektiven ist im folgenden Thread die Rede:

Leica Elmarit-R 2,8/28mm (Leica-R)Leitz Wetzlar Summicron-R 2/35mm (Leica-R)Leitz Wetzlar Summicron-R 2/50mm (Leica-R)Leitz Wetzlar Macro-Elmarit-R 2,8/60mm (Leica-R)Leitz Wetzlar Summicron-R 2,8/90mm (Leica-R)Leitz Wetzlar Elmarit-R 2,8/135mm (Leica-R)
Carl Zeiss Distagon T* 2,8/25mm (Contax Y/C)Carl Zeiss Tessar T* 2,8/45mm (Contax Y/C)Carl Zeiss Planar T* 1,4/50mm (Contax Y/C)Cosina Voigtländer Ultron Aspherical 2/40mm SL (Nikon-F AI-S)Cosina Voigtländer Color-Heliar 2,5/75mm SL (Nikon-F AI-S)Pentax SMC F Fish-Eye Zoom 3,5-4,5/17-28mm (Pentax-K AF) (der Thread ist schon etwas älter, aber trotzdem interessant)

Dort schreibt "rl07":
ZITATI actually remove the R-mount and screw an A-mount onto the lens.

If you own any 1/2/3 cams Leica lens, I do not own any ROM lens, you will see 6 screws position and which 4 out of 6 of them are in EXACTLY the same place to the A-mount. So you can simply unscrew the R-lens mount, take an A-mount from any dirt cheap broken lens and replace it. (actually need a bit more unscrew work)[/quote]
ZITATIt really depends on what A-mount you find and use, for replacement mount with big openning (such as some from old sigma lens), the R-lens aperture lever can move freeing, you only need a screw driver and the whole process is reversible!!

With most A-mount from original Minolta, there are pieces sticking out from the bayonet for dust shield fitting, I need to unscrew more to remove the aperture lever from the lens (3 cams) or even worse for 1 cam, I need to cut the lever off (since I know they cannot be mounted on R10 digital if there are one in future which I cannot afford anyway!! The process is unreversible but who cares.
ZITATIt is hard to say or explain, but since there are 2 screw holes out of 6 which seems unless (remember 4 out of 6 are in exact position compare to A-mount?)

I screw up the other 2 unused with some 'big head' screw to force the other 4 being able to screw-in completely. Which makes the mount about 2mm away from the standard R-mount position, making up the 47mm to fit the lense register distance for perfect infinity focus without loseing close up ability.[/quote]
ZITATWith mount conversion, I do get infinity focus without loseing close focus when the mount is positioned in correct position for R to alpha conversion, please see earlier post for explaination.

With Yashica/Contax, also okay with infinity focus when the replacement mount is thin which I normally use some dirt cheap kenko macro tube as replacement mount.

For Pentax to alpha, I need to use plastic A-mount and cut out the edge of the mount to fit into lens diameter, it is painful. But infinity focus is perfect too.

For Voigtlander (AIS) to alpha, need to drill a few holes on the A-mount, which is painful too but not as bad as K-mount conversion explained. Will focus beyond infinity and loses some macro distance.[/quote]
ZITATLet me open up the mount of Leica 50mm F2 type I converted long ago.
Before that, I choose to take shots with 60mm macro converted earlier.


Could had used 35-70mm macro, 50mm or 100mm Minolta macros...


Notice some opening on the dust shield and bayonet mount to allow the cam or aperture lever movement.



With A-mount removed from lens, notice the 6 screws position on lens?

(2 of them with screws) Compare the other 4 with the A-mount screw positions. They all sits at 90 degrees position.


A close up of the 2 screws, no need to completely screw in



Now I remove the aperture control ring and screw the A-mount back on


Because of the 2 screws between A-mount screws position, they stop the A-mount being able to screw in completely, instead the mount is securely positioned at 47mm desire position for infinity focus without losing macro distance.


Another shot from bottom, you need long screw to achieve this.


Take a look at both A-mount and R-mount, this confirms positioning of screws.


If you get the A-mount from old lens like me. You can use the chip for focus confirmation and SSS.


A shot on Y/C to alpha and K to alpha conversion mentioned in earlier post.
Much more harder to convert~~!


Leica R to alpha is easy but please don't blame me if you DIY and...[/quote]

Siehe auch:

Viele Grüße,


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have been due to individuals of whom the majority faced virulent public opposition."
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RE: Leica-R-Objektive auf A-Bajonett adaptieren

#2 von matthiaspaul , 22.05.2009 11:59

"All the important human advances that we know of since historical times began
have been due to individuals of whom the majority faced virulent public opposition."
--Bertrand Russell (Minolta Forum Thread Index)

Beiträge: 14.595
Registriert am: 08.06.2004


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