Numbers for photographers,
without the black box.

Each tool starts with a practical question, exposes the core relationship and gives a result in units that make sense on a shoot. Where a formula relies on a convention—such as circle of confusion for depth of field—we say so.

Calculations happen locally in your browser. At launch there is no account, no upload and no analytics tracker. The guides are original editorial material designed to add judgement around the output, not to pad a product catalogue.

• State the assumption.
• Use conservative headroom where it helps.
• Separate physical facts from creative conventions.
• Correct material when better evidence appears.