How does a photo finish camera work?

Unlike a normal camera that captures a full frame, a photo finish camera captures a single vertical line of pixels at the finish line, scanning at 1,000+ times per second. The horizontal axis of the image represents time, not space. Runners appear stretched as they cross.

How accurate is photo finish timing?

Modern photo finish systems are accurate to 1/10,000th of a second, though official times are recorded to 1/100th (0.01s) for sprints and 1/100th for distance races. The systems are calibrated to be synchronised with the starting gun.

What happens in a dead heat?

If two runners record the same time to 1/1000th of a second, it is declared a dead heat (tie). In championship races, photo finish images are examined pixel by pixel. In extremely rare cases, both athletes receive the same placing.

How small a gap can photo finish detect?

At a scan rate of 2000 lines/second, the system can detect gaps of 0.0005 seconds. At sprint speeds of ~10 m/s, this corresponds to about 5mm of physical distance — the width of a torso outline.

RunCalcs

Photo Finish Calculator — Time Differences from Photo Finish

Calculate time differences and distance gaps from photo finish images.

Winner's Time

Pixel Gap Between Runners

Image Width

Camera Scan Rate

Race Distance

How We Calculate This

Photo Finish Analysis

The time difference is calculated from the pixel gap in the photo finish image:

Time Difference = Pixel Gap / Scan Rate

Distance Gap = Finish Speed x Time Difference

The scan rate is the number of vertical lines the camera captures per second (typically 1000-2000 Hz). Each pixel column in the image corresponds to 1/scan_rate seconds. Finishing speed is estimated at 105% of average race speed.

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always consult a coach or medical professional for personalised training advice.