A new support page by Apple says that exposing your iPhone to high amplitude vibrations within certain frequency ranges, specifically those generated by high-power motorcycle engines, can degrade the performance of the camera system.
Read the complete article for details, but here’s one thing Apple notes: High-power or high-volume motorcycle engines generate intense high-amplitude vibrations, which are transmitted through the chassis and handlebars. It is not recommended to attach your iPhone to motorcycles with high-power or high-volume engines due to the amplitude of the vibration in certain frequency ranges that they generate. Attaching your iPhone to vehicles with small-volume or electric engines, such as mopeds and scooters, may lead to comparatively lower-amplitude vibrations, but if you do so a vibration dampening mount is recommended to lessen the risk of damage to your iPhone and its OIS and AF systems. It is also recommended to avoid regular use for prolonged periods to further lessen the risk of damage.”