About Camera Math Calculators

Last updated June 9, 2026

Optics arithmetic always seems to matter at the moment it’s hardest to do — on location, light fading, lens change in hand. The calculators on this site exist so that depth of field, equivalence, and exposure math can be checked in seconds rather than re-derived from memory.

In the bag

6 calculators live here: Depth of Field Calculator, Field of View Calculator, Crop Factor Calculator, Hyperfocal Distance Calculator, Exposure Value (EV) Calculator, and Night Sky 500 Rule Calculator. Between them they answer the questions raised when sensor sizes, focal lengths, apertures, and shutter speeds interact.

Assumptions are part of the answer

Depth of field is not a property of a lens alone — it depends on the circle of confusion you accept, so that value is stated on the page and adjustable. Crop-factor conversions spell out what equivalence does and doesn’t equalize. The 500 rule is presented as the rough field heuristic it is, caveats included.

Trust your test frames

These are optical estimates and rules of thumb, not a guarantee of sharpness — circle of confusion, the 500 rule, and equivalence are simplifications, so trust your own test shots for critical work. For critical work, the final authority is your own raw files.

Wrong constant? Say so

Optics discussions attract strong opinions and genuine errors in equal measure. If a formula or constant on this site is wrong, email [email protected] and it will be corrected.