The Carl Zeiss Jena Biotar 1:2 5,8cm (Early, non-preset Version) is a normal prime lens for SLR cameras.
This Biotar, built in the late 1930s, is the precursor of this one: http://allphotolenses.com/lenses/item/c_873.html
It differs from later versions by
no preset aperture
17 aperture blades instead of 13
minimal focusing distance of 90cm instead of 50cm
Filter mount Ø 40.5mm instead of Ø 49.0mm
weight 147gr instead of 206gr
focal distance is marked as 5,8cm instead of 58mm
There were silver and black versions, but the silver finish is rarer. Also the objective was available in two camera mounts: M42 and Exakta, possible also for Praktina.
Links to online resources:
Posted by: Andreas Lindemann Date of publication: 25.07.2017