How do I use a lens gauge and who might be in need of one?

Sebastian Bock · May 18

I found an ARRI 16 BL lens gauge in an old accessories box and I wonder, how to use it. My Arri ST lenses fit in the opening, but I have no idea what this instrument tells me. Who could explain the usage?

And if you're looking for this rare item, drop me a PN. I think, there might be people, who need it more than me.

Here are a few pictures:

Edited May 18 by Sebastian Bock

Dom Jaeger · May 18

It’s a tool to measure the rear protrusion of cine lenses to make sure the lens is compatible with a 16BL. Some earlier 16mm Arri mount lenses protruded too far and could hit the mirror of a 16BL.

Handy tool, since it can check any lens to see if it will clear the mirror on all Arriflex cameras from the 16BL on. The 52.00mm flange depth never changed over the decades, and the minimum mirror clearance remained the same after the 16BL.

Sebastian Bock · May 20

Thanks, Dom, for this explanation.

Have a nice week!

Dom Jaeger · May 20

No worries Sebastian.

It's actually hard to find exact dimensions for 16mm Arriflex camera mirror clearance, so this tool is quite special. It would be great to measure it, or make a mold of the inside, in order to perhaps make 3D print copies of it.