Photography calculator
Photography Exposure Calculator
Change aperture, shutter speed or ISO and see the exact exposure difference plus single-variable settings that preserve the original exposure.
Calculate an equivalent exposure
Load current settings from a photo
Optional. A JPEG or HEIC file is read locally and is not uploaded.
No photo selected.
How equivalent exposure works
Aperture
A lower f-number admits more light. Aperture changes by the square of the f-number ratio.
Shutter speed
Doubling exposure time adds one stop; halving it removes one stop.
ISO
Doubling ISO adds one stop of recorded brightness, with possible noise and dynamic-range costs.
Equivalent exposure does not mean an identical photograph
Two combinations can have equivalent overall exposure while producing different depth of field, motion rendering and image noise. This calculator describes exposure math, not the best setting for a scene. Metering, flash, filters, lighting changes and camera processing can also affect the result.