Large Format Photography
Lenses - Focal Length and Coverage:
All camera lenses for all formats
have a focal length - It is the measurement of the distance from the lens to the film when focused at infinity in millimeters or inches. |
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this is the "burning ants" distance |
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Measure your magnifying
glass focal length by focusing a distant light source on any surface and
measuring that distance. Lens Focal Length - _____________________mm ______________________ inches |
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APERTURES-
F/Stops The f/stop or aperture is determined by the size of the lens opening in relation to its focal length. First measure the focal length of your lens._________________mm ______________inches The size of your lens diameter: __________________mm ___________________inches The f/stop is the
focal length divided by the diameter of the lens (or lens opening). |
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Angle of view: The angle of view
is determined by the focal length AND the size of the film format. The "Normal" lens with about a 45 degree angle of view has a focal length equal or close to the diagonal measurement of the film. Normal for 35mm is 50mm, normal for 4x5 is 150mm |
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A lens that is less
than the "normal" focal length will give you a wide angle view. |
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Our
pinhole cameras have a pinhole that is .5 millimeter (one half millimeter. The f/stop will change with changes in the distance |