Hello all I friend of mine gave me his dads old camera. It's a Zeiss Ikon Tenax with what seems to be a Tessar lens. The markings on front are''Tessar 1:3.5 f=3 3/4 cm T C. Ziess Jena and a serial number in addition to a series of f-stops going from 22 - 3.5. It seems to be in working order, and I just wonder if anyone has any information about the camera. Any infomration is appreciated Regards Birger A.