Published in Spring 1985 Zeiss Historica Journal
Author: Dr. Siegfried Schlegel
See Page 3.
Dr. Schlegel discusses a late Contax I camera for which there is evidence for its existence and a testimony that it was used by a Zeiss free lance photographer and the variance n shutter speeds for the camera as well.
To go to the Journal itself, click on the year, 1985 in the first line above