It is a kind of rolling shutter effect, but you're misunderstanding the finish camera's design - they capture a single column of pixels and the horizontal axis

It is a kind of rolling shutter effect, but you're misunderstanding the finish camera's design - they capture a single column of pixels and the horizontal axis is actually time. This is why the background of photofinishes is a bunch of streaks. https://en.wikipedia.org/wiki/Photo_finish#Strip_photography https://en.wikipedia.org/wiki/Photo_finish#Strip_photography