The first of these appeared in 1945, they was essentially a re-introduction of the Ensign Posometer. At the time they were known as dial calculators, i.e. the disc was moved by notches rather like a telephone dial. The first model was for outdoor use and called the 'British Standard'. The name referred to the British Standard of 1941 on which the calibrations were based. Soon after the name was changed to 'Standard'. The largest aperture was f1.4, later this became f1.5. Around 1948 a model for artificial light was introduced followed in 1954 by a model for flash exposures. In 1957 a 'Colour and Cine' version appeared, this had a slightly different shape to the others. By 1960 the other meters also adopted the new square-top shape.