View Full Version : 75mm Tominon and 150mm Computar or Kowa-Graphic

Steve Goldstein
20-Aug-2011, 11:46
It's not immediately obvious that these should have anything in common, but they do. Herewith a bit of possibly useful trivia for the archives.

I recently acquired some lens cells mounted in a Polaroid Copal 1 shutter. The shutter has a significant internal restriction (see picture) that limits the aperture opening to well below what should be possible in a Copal 1, and a nice engraved speed/aperture scale from 4.5 to 45. It was clear this wasn't the original shutter for these cells. I spent a while pondering what purpose this odd shutter had served, and how I could use it.

After a bit of research I figured out it was most likely the shutter from a 75mm f/4.5 Tominon (searching old eBay auction images was helpful). Hmm, 75mm f/4.5....150mm f/9... In a moment of inspiration I screwed the elements of my 150mm Kowa-Graphic into the shutter. Mirabile dictu, the internal restriction is a perfect match to this lens. Multiplying the engraved aperture markings by a factor of two is all that's required.

I don't have a 150mm Computar, but suspect this type of shutter would work for any of the f/9 150s in the Computar/Kyvytar/Kowa-Graphic clan.