Milner extinction calculator, made by G. M. Milner, San Francisco. Extinction type meter, disc shaped. Reflected light seen through filter is compared with density of rotating step wedge. (M4463) Milner extinction calculator
Heyde's Aktino-photometer made by W.F. Stanley & Co. Cylindrical extinction meter. Rotating continuous wedge moves under blue-glass eyepiece. High-low filter. (See 536 - larger) Heyde's Aktino-photometer
Degen Photo-metre normal exposure calculator, made by Edward Degen, France. Extinction meter: scene viewed through two sliding continuous blue wedges, calibrated for aperture and shutter speed. Presetting one, the other is adjusted to find exposure. Degen Photo-metre normal exposure calculator 1900-1910
Watch form visual exposure meter. Blue filter in eyepiece. Circular continuous wedge. Scales US 1.5-16 f/4.5-16. Exposure times from 6 mins - 1/1000sec. ICA Ica Diaphot Extinction Meter
Eios aktinometer made by Dr. Schlicter, Germany. Extinction type photometer, telescope type.; comparative type with sector wheel adjustment; fields set in diffuser screen. Calibrated H and D 12-2000. (M388) Eios aktinometer extinction meter
Zeiss Ikon diaphot meter. Watch pattern extinction meter in case, with German instructions. Zeiss Ikon diaphot meter. Watch pattern extinction meter in case circa 1925
Disc-cylindrical extinction meter (see 535 - smaller) rotating continuous wedge behind blue glass in eyepieces. 1 scale. Heyde's Aktino-photometer 1905-1935
Heyde's Aktinometer. Extinction meter for use on camera ground glass screen. Manufactured by A. E. Staley and Co, London EC. Heyde's Aktinometer. Extinction meter for use on camera ground glass screen circa 1914