29 November, 2009

DO IT YOURSELF: PINHOLE LENSES

Today I built two pinhole lenses out of two old, damaged M42-lenses.
Yes, "pinhole lenses" is a contradiction, but you know what I mean.

First I cored the two lenses (the glasses must go!), then I put on each lens a lens cap and fixed them. After this I measured the focal lengths and used the pinhole size calculator to determine the diameter of the holes. Later I pricked with a pin the holes in the lens caps.

Now I have two Pinhole-M42-lenses for my M42-slr's!



Focal length: 75mm
Diameter: 0.365mm
fStop: 205
Image circle: 144mm

Original: Revuenon Special 2.8/35mm

Focal length: 55mm
Diameter: 0.313mm
fStop: 176
Image circle: 106mm

Original: Meyer-Optik Görlitz Domiplan 2.8/50mm

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