The term refers to the end of a race that is so close that the winner is only discernable only from a photograph taken as the horses cross the finish line. A common variation is “It’s a photo finish!” or simply “He wins in a photo!”

Grassy Wins the 9th in a 6 horse photo at Saratoga Race Course 8/22/09 photo courtesy of NYRA

An interesting photo of a triple dead heat is here.

Another, more technical, article on the different aspects of the photo finish cameras is here.

Who knew that way back in 1888 a camera on the finish line at a racetrack in New Jersey would usher in the age of instant replay. Now during challenges in the NFL we are treated to super slow motion replays at every conceivable angle. Referees duck under video hoods like the Wizard of Oz behind his curtain. While the time clock on televised basketball games is divided into tenths of a second. It never ceases to amaze me when announcers confidently assure us that there is “no need to rush here, there is still plenty of time to get the shot off” when there are 2.7 seconds left on the clock.

In horse racing the imperfect science of keeping time during morning workouts is still associated with a hand held stopwatch. Race times are now measured by hundredths of a seconds but the time honored method of 1/5 of a second per trailing horse length is still the rule for handicapping. Many of us prescribe to our own methods of finding a Derby winner, but generally, these includes the back of the envelope computations using the finishing times for the last 1/8 mile in recent few prep races. After the injury to Eskendereya the 2010 edition of the Kentucky Derby looks like an evenly matched field, perhaps this the year for a photo finish. For those of you who are interested, a very smart Kentucky Derby system is here.

But I digress, the term photo finish originated at the track yet is used to describe everything from elections to dancing contests in Florida.

I am always surprised when I see the generally unrecognized influence horse racing has on our language and culture. I hope that both horse racing fans and those interested in the English language will also find all of this enjoyable.