Today was Worldwide Pinhole Photography Day.
Pinhole photography involves the use of a camera without a glass lens.
Instead of a lens, beams of light from the subject are directed through a tiny hole to be projected onto a light sensitive plane (such as film).
Light from a particular point in the subject travels in a straight line and can only strike the film at one point, it does not get refracted elsewhere.
The resulting image is the result of all those thousands of adjacent points.
A very small hole means a very small aperture...
thus, pinhole exposures typically have virtually infinite depth of field, and require a long time to get sufficient exposure.

My camera today was a pinhole device I built from a Bolsey B2.
I removed all the glass lens elements and substituted a small aluminum disk with a tiny hole puncture of 1/4 of a mm in diameter.
The hole is set 40 mm from the film plane, so that is the "focal length." Divide that distance by the diameter of the hole, and the resulting value is an aperture rated at f/164.

I loaded the camera with a roll of "Schnucks" branded ASA 400 print film from the freezer, and walked about the house carrying camera, cable release, tripod, a pair of clamp-on lamps with 100 watt bulbs on stands, exposure meter, and conversion chart.
Lots of fun in this.

Please click on thumbnails to enlargement.
All images are ©2012 E.J.Kowalski.