Prosch Duplex brass lens timing issue

[Jody_S]

Photographing falling silver balls in sunlight and measuring the "track" lengths on the plate - well I never!
The balls have to reach terminal velocity.

It's a very simple physics problem to do this if you know the height from which it's dropped, in fact it would work better dropped just above the lens because the classic acceleration formula doesn't account for friction.

[Theerikjohnson]

Thanks all. Good info. I knew I came to the right place.