Industar-50 working distance

[brankop]

I measured lens working distance (WD) of two Industar-50 lenses from 1964 using a collimator and a microscope objective. For a lens focused at infinity and aperture set at f/4, one lens measures 28.683mm while the other one 28.733mm. If I add the maximum allowed film banding (0.05mm) to the lens WD, the result is just on the lower side of recommended camera WD (28.78 mm).

Shouldn’t we take the film base thickness in consideration?

 

[Valkir1987]

Film base thickness varies per type of film. This should be out of consideration. For example: the working distance on a Leica body should be 28.80 with film and without.

Why don't you try measuring wide open, on F 3,5? Most lenses have been taken apart once and miss shims, especially those thin ones.