Re: NuOptix Pulfrich

[P3D Gregory J. Wageman <gjw@xxxxxxxxxx>]

Gabriel Jacob writes:

>So to freeze the action using a film movie camera
>one way it is done is to use a very high frame rate. After this is done
>if it is to be transferrred to a regular video tape, the action would be
>captureed in slow motion. With no blurryness in the fast moving shots. If 
>regular speed motion on playback from the video tape is required then
>a few of the alternating frames would be taken out to speed up the action
>of the original hi-speed film to video without loosing the freeze action.

This isn't quite accurate.  Increasing the frame rate of motion picture
film doesn't necessarily result in less *motion blur*.  While the frame
rate necessarily limits the *maximum* exposure time (since the film
is moving it can only be in the gate for so long), even at three times
the normal 24FPS frame rate, you can still get about 1/80th second
exposure, which as we know from our still work isn't a particularly
"fast" shutter speed.  Depending on your degree of pickiness, speeds
of 1/500th or above are necessary for *really* sharp work if the camera
is hand-held; you can get away with less if a sturdy tripod is used.

High frame rates do result in less 'strobing', aliasing artifacts
(like car wheels appearing to turn "backwards") and smoother apparent
motion, or as you mention, in slow-motion shots when projected at the
normal frame rate.  Using high shutter speeds, a "fast" film stock
and/or high illumination levels is what makes for lack of motion blur,
just as it does in still photography.

        -Greg W.


------------------------------