21. Focal Length, F, used in calculation of f#. f#= F/aperture diameter Example: F=Distance from aperture to film plane = 8 inches Aperture diameter = .5mm Convert inches to mm: (8 in) X (25.4 mm/in) = 203.2 mm f# = 203.2mm/.5mm = 406.4 http://www.mrpinhole.com/holesize.php
23. f406 Our meter tells us our bright daylight scene requires an exposure of f22 @ 1/30 sec
24. f406 Our meter tells us our bright daylight scene requires an exposure of f22 @ 1/30 sec f22 f32 f45 f64 f90 f128 f180 f256 f360 f512 1/30 1/15 1/8 1/4 1/2 1 2 4 8 16
25. f406 Our meter tells us our bright daylight scene requires an exposure of f22 @ 1/30 sec f22 f32 f45 f64 f90 f128 f180 f256 f360 f512 1/30 1/15 1/8 1/4 1/2 1 2 4 8 16 We will need an exposure time of approximately 10-12 sec