What is this lens?

[Heldur]

Well its a zeiss jena tessar 80mm 2.8, but why does it have a curve on the back end??? and what cameras does the lens fit?

 

[Limpovitj]

If I'm not mistaken, that one fits the (German, pre-war) Reflex Korelle 6x6cm SLRs. It is cut of like that to allow clearance for the mirror as it goes up.

 

[Heldur]

Thats impressive, thanks. THeres one for sale on Ebay for $13 (auction), I couldnt work out why the lens had a cut out section