I was wondering if anyone has any experience with the 8x10 version of this pinhole camera. Does the image circle cover the entire 8x10 frame? Or is there vignetting on the edges?

The only photos I've seen on the net have been from the 4x5 version and that covers the entire frame from what I can see...but I'm more interested in the 8x10 version.

Thanks.

-- Scott Gant (sgant@interaccess.com), August 18, 1998

Answers

I've no experience with that particular camera, but pinhole cameras in general obey the cos^4 law, which means that illumination at a point on the film falls of by the fourth power of the cosine of the angle at the pinhole between the pinhole axis and the point.

As an example, suppose the pinhole is 300mm from the film. 10x8 film has a semi-diagonal of about 162mm. So, for a point in the corner, the angle is atan(162/300) = 28 degrees. Cos(28) is 0.88, raised to the fourth power is 0.6. So the fall-off is less than one stop.

-- Alan Gibson (gibson.al@mail.dec.com), August 21, 1998.