I've been given a Zeiss Ikoflex IIA TLR with a Tessar in near mint condition but I cannot see how to get the frame counter to operate. As I don't have an instruction book can anyone please help. Is there someone who still uses an Ikoflex like this. It has a serrated button which appears to have to be pressed and turned in an anticlockwise direction - but when, and how far ? <p> I should appreciate any help you can give me.