1936: A photo-finish camera is installed at Florida's Hialeah Race Track. It marks the first use of the device for thoroughbred horse racing, the sport with which it is most closely associated.
Aside from the ponies, photo-finish cameras are used at track meets, in auto racing and in bicycle racing -- anywhere, in fact, where the winner is determined by competitors hitting a finish line.
The photo-finish camera was originally a conventional still camera modified to handle rapid multiple imaging by replacing the focal-plane shutter with a capping shutter and employing a vertical slit-view of the finish line. The camera was elevated to avoid blocking the view of any one competitor.
With refinements, which resulted in a dramatic increase in the number of photographs taken per second, this remained the basic photo-finish technology until the advent of digital photography. A camera in the mid-20th century might shoot 100 images per second. Modern digital cameras can take 1,000 images per second.
The first photo-finish camera was used at the 1912 Olympic Games in Stockholm. By the 1932 Los Angeles Games, photo-finish technology had advanced to include both the finish line and a chronograph reading on a single image.
A version of this so-called Kirby camera went into use at Hialeah for the 1936 meeting.
In horse racing, the winning horse is the one whose nose hits the line first. In a race between humans, it's any part of the torso, which is why you often see runners lunging at the tape in a close race.
Perhaps the most famous photo finish of all time occurred with a triple dead heat (three horses hitting the finish line simultaneously) in the 1956 Hotham Handicap at Aqueduct Racetrack in New York.
(Source: Various)
This article first appeared on Wired.com July 4, 2008.
