I want to make lens hood for my LTM Elmar, from black duct tape. The question is - how long can this hood be? Is 2cm too much? Anybody here has done this already?
I haven't made a hood for one but at the 50mm setting my FIKUS adjustable shade is approx 25mm deep with an inside diameter of approx 40mm. Hope this helps.
A quick check with a 1953 50mm f/3.5 LTM Elmar indicates that a cylindrical lens hood with the inside diameter equal to the 36mm outside diameter of the lens front could be up to 2.5cm before vignetting occurs.