Pinhole Camera
A lensless camera that forms an image through a tiny aperture, giving infinite depth of field and extremely long exposures.
Formula / rule
d = √(2 × λ × f)
Measured in
mm
In depth
With no lens there are no aberrations, no distortion and no plane of focus — everything is equally, softly rendered. The optimal hole diameter is a balance between geometric blur, which favours a smaller hole, and diffraction, which favours a larger one. Effective apertures typically land between f/150 and f/300, so exposures run to seconds or minutes even in daylight.
Examples in practice
A 0.3 mm pinhole at 50 mm from the film gives roughly f/170, needing about four seconds at ISO 100 in full sun.