View Full Version : Leonardo 8x10 Pinhole cameras and image circle

Scott Gant
18-Aug-1998, 19:04
I was wondering if anyone has any experience with the 8x10 version of this pinho le camera. Does the image circle cover the entire 8x10 frame? Or is there vignet ting on the edges?

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


Alan Gibson
21-Aug-1998, 07:00
I've no experience with that particular camera, but pinhole cameras in general o bey 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 pinho le 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(162/30 0) = 28 degrees. Cos(28) is 0.88, raised to the fourth power is 0.6. So the fall -off is less than one stop.