In 1932, at the Olympic Games in Los Angeles, a remarkable device, invented by Gustavus T. Kirby, made its appearance. Known as the "Two eyes camera", it had, on the same image, one eye on the finish and the other on a digital chronograph controlled by a tuning fork clock. This camera recorded at a rate of 128 images per second and allowed hundredths of a second to be read with ease. In the final of the 100 metres, Tolan and Metcalfe reached the finish line together, but Tolan was declared the winner because his torso crossed the line completely before that of Metcalfe, as the camera film showed. That was the rule at the time. The rule was changed after the event so that only the first part of the torso was taken into consideration.
The camera was also called "Kodak- Bell Lab's" after its inventors,
and it was sold under the abbreviation ERPI (Electrical Research Products Inc.),
a subsidiary of Bell Systems. In 1936, for the Olympic Games in Berlin, the
company Zeiss- Ikon AG of Dresden and the Physikalisch- Technischer Reichsanstalt
development together the "Ziel- Zeit Camera". Based on the same principle as
the Kirby camera, it generally recorded, for practical reasons, at 50 images
per second. Its time base was provided by a marine chronometer. Two cameras
filmed in perfect synchronisation. One was aligned on the finish line and the
second slightly forward of the line. As a result, it was possible to see films
of the finish in relief by use of polarising lenses.
In 1950, Longines came up with the Chronocinégines, controlled by a quartz clock. It obtained chronometric observatory results showing no time variation greater than one hundredth of a second in 24hours.
The chronocinema technique was used again in 1964 at the Olympic Games in Tokyo for the rowing competition.