The commissaires had to resort to the photo finish to designate the winner of the 7th stage of the Tour de France, Friday, in Chalon-sur-Saone (Saone-et-Loire). At real speed and with the naked eye, it is difficult to decide between Dylan Groenewegen (Jumbo) and Caleb Ewan (Lotto). Indeed, a hundredth of a second separates them, that is 17 cm. But how does the photo finish work?
"All the riders' bikes are equipped with a transponder that we use to identify them," explains Alain Zobrist, general manager of Tissot Timing, official timekeeper. Then, on the line, are arranged three cameras that take 10,000 photos per second. All clichés are collected and allow the commissioners to designate in a few seconds the winner.
A team of eight people moves every day on the line. The number of people who go up to 17 on the days of the time trial also manages intermediate sprints where cameras have also been installed for the first time.