Re: Image sharpness and focus distance.

[Bill Glickman <bglick@xxxxxxxx>]

Les

      Well said....so I assume that the roundshot 220VR, when it asks you
for the focus distance, it adjust the film travel speed accordingly?   I
originally thought it was used only for setting of the nodal point of the
lens?  Does anyone know if this is true on the 220VR?

Bill G


> This is true for still cameras but not rotational cameras since with a
> rotational camera you are photographing the interior of a cylinder (the
> focus point). The speed at which the film travels through the camera
> (not to be confused with film speed!)must be matched to the focused point.
>
> Assume a camera is focused and set up for a point 30 feet away.
>
> Since the circumference of a cylinder 30 feet away is vastly larger than
> a cylinder 20 feet away, the film will travel at the wrong rate for the
> shorter distance and be seen as soft or blurred inspite of the fact that
> this point fell within the limits of depth of field.
>
> Les