Biotar 1:2/4 cm

[UliWer]

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As the 1:2/4cm (also named 4.25 or 4 1/4) Biotar is a very rare - and one of the most expensive - lenses for the Zeiss ikon Contax I preferred to ignored it.

Though Ecar's examples here stifled my interest again:

 

As Ecar mentioned the version for the Robot, can you tell whether this version will work on full frame (the Robot was only half-frame)?

And do you see any possibility to adapt the Robot version to the Leica?

 

 

[Biotar]

Hi Uli

Yes it works on FF - i already used Robot-Biotar and Tenax-Sonnar 2/4cm 10 years ago on Sony alpha 7r with these great results. ... and it was in Hamburg

U can find M26 to L39 adapters for the robot on ebay.

Marcus

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[zeitz]

1 hour ago, UliWer said:

the Robot was only half-frame

Robot used many different film formats.  The Robot common was not half-frame 18 x 24; it took a square image 24 x 24.  Some later Robots were half frame or full frame 24 x 36.  Robot Recorders could have 6 x 24, 12 x 24 or 16 x 16.  There were three lens mounts.  There was a very early 26 mm diameter x 0.75 mm pitch; the common screw mount 26 mm diameter x 1.0 mm pitch; and the Robot Royal breech mount was 31mm diameter x 1.0 mm pitch.

[Ecar]

I believe the Robot-Biotar 40/2 does indeed cover FF. Only reason I went for the original Contax version is that I dislike the big, toy-like ROBOT markings on the lens itself. The obvious downside is price, as these Contax versions are quite rare.

Also, when using adapters, do bear in mind that you won't get RF coupling, so you are limited to LV/EVF-enabled cameras.

Since I like using the RF, I had my copy (non-destructively) converted to M by fitting a new, custom helicoid. The lens won't fit in an Amedeo Contax->M adapter and its focal length is under 50mm, so focus would have been off anyway.