Calculate Depth of Focus for Digital Cameras
copyright: Lindolfi
Enter Values:

Viewing Distance to Photo (mm): 250 mm is reading distance
Photo Length (mm): 150 mm is standard  postcard length
Resolution human eye in degrees: 0.02 is about right
Chiplength (mm): see Steve's Digicam Database or the manual of your camera. Look for the specifications (size) of the CCD. NB: some produces give the size in inch (25.4 mm), or only the diagonal!
Example: D70: 23.7 mm.
Number of pixels longest side of chip: also depending on camera setting,
D70 6 megapixel: 3008 pixels
Focal length lens (mm): the real value, do not include crop factor!(
Stop number: from camera
Focus distance lens to object (mm): estimate or use measuring tape:

Lens opening (mm) the real opening of the lens
Size of 1 pixel (mm) in photo visible eye limited
Size of 1 pixel (mm) in chip visible eye limited
Size of 1 pixel (mm) due to diffraction limitation due to small opening
Size of 1 real pixel (mm) in chip the real size
Limiting pixel size in (mm) pixelsize that is just visible
Image distance (mm) distance lens to chip
Image distance further (mm) distance lens to image of object further from camera
Image distance closer (mm) distance lens to image of object closer to camera
Object distance further (mm) distance object-lens further from camera
Object distance closer (mm) distance object-lens closer to camera
Depth of Focus (mm) final result

Hyperfocal Distance (m) focus distance for which the image will be in focus up to infinity

Met dank aan Helco van Keeken