# Pinhole insanity or f/64

Geeking out on camera stuff lately.

An interesting project is the quality Canon EOS pinhole lens.

I’ve got it completely engineered and the hard parts solved. I just need to get up off my butt and make it. It’s funny how some simple projects sit. Maybe posting this will spike some interest.

Designed around 34mm EF-S f/129.7 and f/64. 34mm is a ‘normal’ lens for EF-S, equivalent to 54.9mm for EF.

Note 34mm was the shortest ‘literal’ focal length possible on my Canon 40D camera. Any shorter and the mirror would be blocked.

Lord Rayleigh’s formula: (a rule of thumb for pinhole apature diameter)

d = 1.9 x √ (f x λ)

where

d is the diameter of the hole

f is the focal length (the distance from the hole to the sensor or film)

λ is the wavelength of the light

For visible light, the average wavelength is 0.56 mm (0.00056mm)

f = 34 mm EF-S (equivalent to 54.9mm EF, 44.9 degree diagonal view) Note: This is the minimum mechanical focal length possible on my Canon 40D.

d= 0.262 mm or 0.0103″

F-stop = f / d

Thus, f/129.7

For f/64, d = 0.53125mm or 0.0209″

For f/64 (See: Group f/64)

http://www.geocities.com/markhahn2000/pinhole_concepts.html

http://www.photostuff.co.uk/pinhole.htm

http://www.flickr.com/photos/dominicspics/4589827160/