G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
G01J1/00—Photometry, e.g. photographic exposure meter
G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
G—PHYSICS
G06—COMPUTING OR CALCULATING; COUNTING
G06G—ANALOGUE COMPUTERS
G06G1/00—Hand manipulated computing devices
G06G1/02—Devices in which computing is effected by adding, subtracting, or comparing lengths of parallel or concentric graduated scales
G06G1/10—Devices in which computing is effected by adding, subtracting, or comparing lengths of parallel or concentric graduated scales characterised by the graduation
G06G1/12—Devices in which computing is effected by adding, subtracting, or comparing lengths of parallel or concentric graduated scales characterised by the graduation logarithmic graduations, e.g. for multiplication