Special Watkin's Diaphragm designed to give equal spaces between U.S. values for a calculating shutter

Made:
1902
maker:
Alfred Watkins
Special Watkin's Diaphragm designed to give equal spaces between U.S. values for a calculating shutter

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Special Watkin's Diaphragm designed to give equal spaces between U.S. values for a calculating shutter, c. 1902.

Details

Category:
Photographic Technology
Object Number:
1927-960
Measurements:
overall: 20 mm, 40 mm, .03 kg
type:
diaphragm - optical
credit:
Watkins, Alfred