Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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
G01J1/10—Photometry, e.g. photographic exposure meter by comparison with reference light or electric value provisionally void
G01J1/12—Photometry, e.g. photographic exposure meter by comparison with reference light or electric value provisionally void using wholly visual means
G01J1/122—Visual exposure meters for determining the exposure time in photographical recording or reproducing
G01J1/124—Visual exposure meters for determining the exposure time in photographical recording or reproducing based on the comparison of the intensity of measured light with a comparison source or comparison illuminated surface
G01J1/126—Visual exposure meters for determining the exposure time in photographical recording or reproducing based on the comparison of the intensity of measured light with a comparison source or comparison illuminated surface for enlarging apparatus