The Drem company was founded around 1924, the Justophot, designed by Dr. Emil Mayer, must have been one of the first products. A cine version was introduced about the same time. In use the tube is set to one of four values depending on the judged light level. The value corresponds to a shutter speed. When looking through the finder the value can be seen and by turning a ring, which controls an iris, the extinction point is set. The correct aperture is now shown opposite an index on the meter barrel. To find an alternative shutter speed or aperture a ring showing shutter speeds is also set against the index. The settings are for 'normal' emulsions, for other speeds a third ring is set against the shutter speed and gives a new shutter speed.

Early models have black painted bodies and a round eye-shade to the finder. Later the tube length was increased slightly and a contoured eye-shade fitted. In 1928 the sensitivity was increased. In c. 1930 a chrome finish to the body was used and the tubes were slightly shorter. In 1933 the operation was improved by setting the plate speed when first using the meter, the setting remained in effect for subsequent readings. An improved model of the Cinephot was introduced in 1928. The calibration of the plate speed ring varies. At some point models were produced for long or short sight. Model designations vary but at one time the model for normal and short sight was called Model I and for normal to long sight Model II. An E suffix denoted that the aperture scale was for England.