Calculator for decrease in focal length (increase in power) due to 'fixed' image distance
Enter the focal length corresponding to viewing infinity in cm NOT mm:
Enter the object distance in cm NOT metre/mm:
Decreased focal length is cm.
DoF (Depth of Field) Calculator; Use this calculator to Calculate pinhole effect due to pupillary contractions
Enter the decreased focal length of the lens in cms (it usually changes depending upon the object distance).
A calculator for decreased focal length is provided above.
Enter the Aperture number/F-number (N)
If you know the Aperture size (diameter) instead, use this F-number calculator and THEN ENTER N ABOVE.
Enter the Aperture size in mm NOT CM:
The F-number is
Enter the value of Circle of Confusion (C.o.C) in mm:
Enter image distance formed by the lens in cm NOT mm (In most lenses, this is the reported focal length)
Your r is focal units.
Your k is focal units.
Your j is focal units.
The angle subtended by Aperture from object is degrees.
The angle subtended by Aperture from image is degrees.
Your j_close is focal units.
Your j_distant is focal units.
Your k_close is focal units.
Your k_distant is focal units.
Total DoF for the given CoC comes out to be cms.
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