Photo Finish Camera
In 1926, two technicians employed at the R.A.F. experimental station at Farnborough. England, invented a camera for the purpose of accurately timing aircraft. Based on that principle, the first photofinish camera ever used for horse-racing or other such purpose, was built and later installed at the Santa Anita track, U.S.A., in 1937.
The photo-finish camera in use at most of the leading, racecourses in Australia was designed by Shmith and Pearl, and was first used experimentally in Melbourne in 1945. This camera is a simple yet ingenious device that tells with 100 per cent, accuracy the result of a horse race. It also indicates visually, the time margin separating each horse to the nearest one-hundredth of a second.
The main point about the Australian photo-finish camera is that only a thin section of track, 2 inches wide, and the dead center of the winning post is viewed by the camera. NO other part of the course is filmed. Thus in any photo-finish print only the winning post area is shown, and no record whatever is provided of events occurring outside these two inches of turf.
The camera is started just before the horses reach the line, and it continues for the next ten seconds, filming all horses as they cross over. The camera is installed at a convenient elevation and on an extension of the finishing line. As the horses pass the two inches of track covered by the camera, they are automatically photographed. The picture is built up out of a continuous series of thin slices, two inches at a time; but in fact these slices join together to make a complete whole for as they come through the lens the moving film keeps pace with them.
A continuous picture is thus obtained, for the j speed of the film is synchronised with the speed of f the horses. When this is not so, distortions occur, but the placings would still be valid.
The winning post viewed by the camera is fitted with a high intensity mercury discharge tube, recessed about six inches, and set vertical. This tube is adjusted to remain alight for 9/1000 second and dark for 1/1000 second. When alight it shows white in the photograph, when dark it shows block. The result is a series of black parallel lines on a white background. The distance between adjacent black lines represents 1/100 second, so that the difference in the finishing time of each horse is accurately shown. For example, if the first horse finished 17/100s of a second before the third horse a photograph is obtained from the opposite side of the track also, a mirror is fitted into the winning post. This is very helpful where many horses are bunched together very closely at the post.