Depth of field

Depth of field describes the range of object distances that meet a chosen acceptable-blur criterion. In Photivra, the criterion is an explicit caller-supplied circle of confusion rather than a hidden sensor threshold.

Inputs that matter

• Focal length: changes magnification and focus geometry.
• Aperture: a wider entrance pupil produces larger geometric defocus away from the focus plane.
• Focus distance: determines the selected image plane.
• Circle of confusion: defines the acceptable geometric blur criterion.

Photivra returns near and far limits plus total geometric depth of field. An unbounded far limit is represented as infinity rather than an invented finite distance.

Model limits

The depth-of-field criterion is geometric. It does not fold diffraction, aberrations, sharpening, demosaicing, display size, viewing distance, or a complete image-quality model into one number.