EXTINCTION CLOCK good 1922 Exposure Mtr

Product Name: EXTINCTION CLOCK good 1922 Exposure Mtr
1922 ICA Extinction Meter Diaphot I've never seen one in such amazing shape w the case and instructions. No cracks in the glass, no scrapes, no corrosion. Leather case is perfect... not dried out and stitching is great. Not bad for 100 years old! This one is pre-war... post-war has a different name on the back. A very simple disc type extinction meter. The subject is viewed through the eye-piece, turning the rim of the case causes a variable density wedge to rotate across the field. At the indistinct point the shutter speed and good aperture pairs can be read on the front of the meter. A blue glass filter is used to view the subject. Pristine condition and highly collectible.