Description
JOHNSON STANDARD EXPOSURE CALCULATOR
Johnson Standard Exposure Calculator. This was the earlier form of the “Standard” calculator, dating from the early 1950s
In the days before exposure meters became the norm, a whole range of calculators were available to enable the correct exposure to be determined in both daylight and artificial light. Some were film or camera make specific, such as those by Kodak, whilst others were generally applicable, such as the range produced by Johnson of Hendon in the UK.
In late 1946 (RH), Johnson & Sons, Manufacturing Chemists Ltd, began marketing a ‘British Standard’ (to BS 935/1941) 6.5cm diameter rotary exposure calculator made of ‘ivorine’. This plastic simulates the appearance of ivory. It was reviewed in the 4th December 1946 issue of the British Journal of Photography (BJP) on p132. “Packed in a stout envelope, with full instructions, the price is 4s/2d (21p) including Purchase Tax” (PT). The full review is viewable here, together with the Johnsons advert in the 1947 BJP Almanac.
Johnson Standard Exposure Calculator for Black & White & Colour Negative Films in Daylight. Another calculator from the range of Johnsons of Hendon Ltd. It also has its paper envelope and instruction sheet, the latter with a printing date of 1968. Construction is the same as for the Colour one above. The filter factor was set against ‘start’ in using first, and then the subject group was selected and dialled to ‘stop’. Then the calculator was turned over, and the light value, the film speed and weather conditions were successively dialled. Then, on the calculator’s front, the shutter speed could be read off against the chosen aperture.
Its construction is the same as the Flash calculator. It is made of Ivorine (Celluloid). Its operation was similar to that of the later model but using Time rather than Light Value.
Johnsons Catalogue:
