Another link when I decided to run my Harry’s LapTimer on my iPhone. Pardon the shaky video. I don’t think iPhones have image stabilizing features like my go pro does or either that cheesy rear view iPhone mount I bought needs a modification (ie small bungee). Funny thing. My fastest consistent session of laps around 2:30 were not captured on video as in about the 3rd turn it came flying off the clamp mount and hit the floor. So it captured the ceiling of my Camaro the entire session.
https://youtu.be/RTE1Byt8qVc