F-Stop Calculator
Find equivalent exposures by comparing aperture, shutter speed, and ISO combinations that share the same exposure value (EV).
Reference Exposure
Exposure Value
—
EV at ISO 100
Equivalent Exposures
Same EV — different aperture, shutter, and ISO combinations
| Aperture | Shutter | ISO |
|---|---|---|
| Loading... | ||
Full F-Stop Scale
Standard aperture values with full, half, and third stops
| f-number | Stop type | Stops from f/1 | Light (relative) |
|---|
Summary
Find equivalent exposures by comparing aperture, shutter speed, and ISO combinations that share the same exposure value (EV).
How it works
- Enter a reference aperture (f-number), shutter speed, and ISO.
- The calculator computes the Exposure Value (EV) using the APEX formula: EV = log2(N² / t) + log2(ISO/100).
- All standard aperture, shutter speed, and ISO combinations matching that EV are listed.
- Browse the equivalent combinations — any row gives the same exposure.
- Scroll down for the complete f-stop scale table showing full, half, and third stops.
Use cases
- Switch from a wide aperture to a smaller one while keeping exposure the same by adjusting shutter speed.
- Find a faster shutter speed for action shots without changing exposure.
- Determine what ISO change compensates for a shutter speed limit on a gimbal.
- Understand how each f-stop doubles or halves the light reaching the sensor.
- Teach exposure triangle concepts with a clear visual reference.
- Plan a long-exposure substitution: same EV at f/16 and a 30-second shutter.
Frequently Asked Questions
Last updated: 2026-06-11 ·
Reviewed by Nham Vu