Focal Depth	Royalty free photographs http://www.focaldepth.co.uk
	f6.3 flen=200mm size=400x600 f8 flen=200mm size=400x600 f6.3 flen=100mm size=400x600 f8 flen=100mm size=400x600 f6.3 flen=50mm size=400x600 f8 flen=50mm size=400x600 f6.3 flen=200mm size=200x300 f8 flen=200mm size=200x300 f6.3 flen=100mm size=200x300 f8 flen=100mm size=200x300 f6.3 flen=50mm size=200x300 f8 flen=50mm size=200x300
	Focal Depth depends on, lens aperture, focal length and focal distance. Focal depth also depends on either the resolution of the image sensor or the resolution of the final image. The above examples illustrate focal depth in action. A simple formula for depth of focus is given as follows: Dfar = cof * Fno * D * D / ( f * f - cof * Fno * D) Dnear = cof * Fno * D * D / ( f * f + cof * Fno * D) Df = Dfar + Dnear Where: Dfar Far limit of depth of field Dnear Near limit of depth of field Df Depth of field cof Circle of confusion Fno Aperture F number f Lens focal length D Folac distance
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