Slit pinhole.

[Isis]

Going to make a single slit "pinhole" camera. Im thinking that you set the width of the slit like normal, ie .3mm at 45mm but the f stop is worked out on the area. Is this right, or how do I work out the f stop.

[Jim Jones]

Exposure is determined by the area of the pinhole or slit.

[Isis]

Thanks Jim. Am i correct in thinking that the slit width is the same as the diameter of a pinhole for a given film to pinhole distance?

[Jimmy G]

Hi Shane,
If it were me I would use the width of the slit to determine the f number, then reduce by X number of stops, X being the number of times longer (minus 1) the length of the slit is to the width.
Example: slit 3 times longer than wide - reduce by 2 stops.
(This also agrees with Jim on the 'area').
Also, I would go with what you said about optimizing for the slit width.

[Isis]

Thanks Jimmy, and that 6x6 your building looks stunning.