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Re: Shooting 25fps locally



Hi, since I think I started this, 

I believe That it goes something like this.

144 degree shutter angle,  at 24 F.P.S. for filming off of a T.V.
set.(N.T.S.C.) 
Also you need to be able to phase (slightly slow the camera down momentarily)
to clear the Roll bar on the monitor. (I've done it, however, it only works
on Broadcast, Shooting off a VHS machine doesn't work, as the VHS speed is
not precise, and the Roll bar creeps in.)

150 degree shutter at 25 fps, for shooting in countries with 60 HZ
electricity.

172.8 Degree shutter at 24 F.P.S. for shooting in countries with 50 Hz
electric.

The Formula is of course:

1/(frame rate ) Multiplied by  (Shutter angle)/360 = Exposure time.

50 Herz is .02 (1/50)
60 Herz is .016666666... (1/60)

About shooting off the monitor, that is in a lot of books, The Jon Fauer 35mm
book.
Also found it in the American Cinematographers Manual, seventh Edition . That
section by Bill Hogan.
However,  I've found the best way to shoot T.V. screens is to sync the camera
up to the monitor, thus ensuring an exact lock, and no drift. Cinematography
electronics makes such an Item.
This is probably more than you all wanted to know, sorry.
Shooting with different shutter Angles will give a slightly different look,
it will effect safe panning speeds (look out for the dreaded jittering
image), but for lock offs, No one will PROBABLY notice.
Glad to share
Steven (been a long time since I had to figure that out ) Gladstone


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