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:
DfarFar limit of depth of field
DnearNear limit of depth of field
DfDepth of field
cofCircle of confusion
FnoAperture F number
fLens focal length
DFolac distance
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