Free tool
Exposure Calculator
Solve for the shutter speed at any aperture, ISO and filter combination.
Inputs
A sunlit subject is around EV 15. An indoor room in the evening is around EV 5.
Seconds. 1/125 s = 0.008.
Recommended shutter speed
1/125
at f/8 · ISO 400
Working EV—
EV at ISO 100—
ISO stops from 100—
Mode—
Reciprocity—
—exposure range
Equivalent pairs
What this calculator does
Enter a metered EV, your aperture and your film speed. The calculator returns the correct shutter speed, an EV breakdown, and a full table of equivalent aperture / shutter pairs — with a reciprocity warning when the exposure gets long.
Inputs
- Metered EV at ISO 100
- Aperture (f/)
- ISO
- Filter compensation in stops
- Lock aperture or shutter
Outputs
- Recommended shutter speed
- Working EV
- Full equivalent-pair table
- Reciprocity-corrected time
- Exposure-range gauge
Educational estimates. This calculator uses published approximations and standard photographic relationships. It is a teaching aid, not a substitute for the data sheet supplied with your film, developer or paper, and it makes no claim about the result you will get. Verify every figure before you rely on it.