The average human reaction time
is between two tenths and three tenths of a second.
The average reaction time of an Olympic athlete
is a bit quicker, not surprisingly.
But the fact is that, when you're using a stopwatch,
there will always be a small
but significant difference between
the moment the gun goes off and
the moment the thumb hits the button.
It's just human nature.
And yet it was the stopwatch -
this human-operated instrument, not-quite accurate -
that recorded Olympic events right up to the 1960s.
A moment of human distraction
could make a serious difference to the official results.
Nowadays, we take it for
granted that races are automatically
timed with precision, measured
to within a hundredth of a second,
sometimes a thousandth of a second.
So today, we're able to test the speed and reaction time
of the athletes, not the timekeepers.
There were other limitations to using stopwatches.
At the first Olympic Winter Games in 1924,
timing ski races over
long distances, at high altitude,
presented a real challenge.
The most sophisticated solution they could find
was to use two coordinated stopwatches -
one at the top and one at the bottom -
to record start times and finish times.
But with no telephones on the
mountain to communicate the data
from top to bottom, that meant
that the race would have to be completed
and the figures calculated
before anyone had any idea who had won.
Trying to think of the quickest way to get the information
from top to bottom, one timekeeper
came up with a creative solution.
So...this is your start time -
if you could give it to the timekeeper
at the bottom of the hill, that would be marvellous.
And ready, set, go.
Pip-pip!
Olympic timekeeping has come a long way since those days,
and one key piece of technology has vastly improved the science
of measuring victory -
the photo-finish.
The idea of using a camera to record the winner
was first developed in horse racing in the 1920s.
The photo-finish camera records
not the distance between the runners,
but the visual time in 50ths of a second.
In the real photo-finish box,
shutters over the windows transform it into a darkroom.
Into the developing tanks goes
the picture, which, if the judges
have disagreed, will settle the result beyond all argument.
And here's the finish,
30 seconds after the race is over.
Hard luck, chum, but the camera can't be wrong.
The photo-finish was first used
at the Olympic Games in Los Angeles in 1932.
The men's 100m final would come down
to two American sprinters -
Eddie Tolan and Ralph Metcalfe.
A hundred-metre dash.
Yoshioka snaps off first and
that's Tolan sprinting to the front now.
He's ahead, Metcalfe a foot behind.
Now Tolan and Metcalfe seem even.
Can you tell who won?
Both were given the same time - 10.38 seconds,
using a stopwatch, of course.
The photo-finish eventually determined the correct winner.
Tolan wins. The world's record
of ten and three-tenths seconds.
The world's fastest humans.
Tolan first and Metcalfe second,
both of the United States,
and Arthur Jonath of Germany third.
But there was a snag.
Developing film was a complex art,
and it took a while in the darkroom.
A long while.
It was several hours later
before the timekeeper was able to
declare Eddie Tolan the winner.
He was deemed to have got his
entire body across the line first.
In more modern times, the winner is the first athlete
to cross the line
with any part of his or her body.
Judged by modern rules,
Metcalfe, not Tolan, would have won.
But those are human rules and human interpretations.
Another day of the Olympic Games
and there's no let-up in the game
competitions before huge crowds,
despite the London mist.
By the London 1948 Olympic Games,
the technology had moved on again.
Timekeepers managed to get the photo-finish result out
in less than 90 seconds -
quite an achievement in those days of pre-digital technology.
On their marks, set, and they're off.
with Dillard on the outside, getting away in front.
Now, as we watch the race in slow motion, left to right,
it's Dillard, Bailey,
McCorquodale, La Beach, Ewell and Patton.
Dillard still holds his lead,
with Ewell resolutely closing down.
At the tape, it's a photo-finish.
The winner was clear enough.
But the photo-finish was
required to award the bronze medal
and the silver medal.
Again, the photo-finish was really showing its worth.
Let's do our own photo-finish.
Yeah, let's do it.
Have I got something in my teeth?
Digital cameras today capture
images at 10,000 frames per second,
allowing instant photo-finish results.
No Olympic Games goes by
without several races coming down to
a nail-biting, thrilling -
but perfectly accurate - photo-finish.