[planede]

Well, camera placement matters in the obvious way: it has to be on the finish "line". Where "line" is really a plane extending vertically from the line drawn on the surface.

I vaguely remember an article about a bike race photo finish that showed that this is not a given and reverse engineered where the camera was pointing (based on background) and who the likely winner was.

edit: found it https://www.tglyn.ch/blog/amstel_gold/

[Luc]

Great link that.

But in the end, if I am not mistaken the UCI rules state that the photo finish line is the final arbiter, not the paint on the ground. I don't think this is a great injustice - it's a sport and the rules are arbitrary to a great extent (e.g. male riders 180 cm to 189.9 cm tall must use a smaller bike than those 190 cm and taller in time trials - which sucks for those 189.9 cm tall).