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Re: MBL, was Re: Air resistance



A few years ago, a similar idea occurred to me but I never carried it out.
Steve I'm glad you did. The idea occurred to me while watching the movie,
Cannery Row. Nick Nolte plays "Doc" in the film. At one point the scene
shows Doc laying on his bed and repeatedly throwing a baseball straight up
above him and catching it as it falls back down toward him. Doc lives in
his lab (he's a pro baseball pitcher turned biologist) so the ceiling in
the room is apparently fairly high. The scene appears to be filmed in
telephoto so there is this sensation of the ball getting bigger and then
smaller while the whole scene stays in focus.

This is not what one would expect of telephoto. The apparent change in the
size of the ball is *minimized* by telephoto which foreshortens distant
subjects seen large. I expect the scene was filmed at small aperture rather
than long focal length if the changing size of the ball is evident.

But the reason I write is that this question can be answered definitively!
If someone will get me the following data I will be able to tell you just
what focal length lens was used. I need the ratio of the ball diameters at
top and bottom and the number of frames covered by a throw. I don't even
need the format of the film (likely 35 mm or 65 mm) to do this calculation*.
This makes a great problem, I think. Anyone out there have a videotape of
"Cannery Row"?

I have wondered whether one
could take diameter vs time data on the ball and determine "g" or other
things from this. (I doubt that air resistance would be extremely
significant for a baseball, given the heights that might be achieved during
the throw.)

Leigh

*Knowing the format I can tell you whether the lens is a telephoto or not,
or at least whether it is a long lens or not. "Telephoto" means something
specific. One cannot tell the difference between a telephoto picture and a
telescopic picture.