Exposure Triangle Calculator
Change one exposure setting (aperture, shutter speed, or ISO) and calculate the compensating adjustment to maintain the same exposure.
The Exposure Triangle describes the interdependence of three camera settings that together control how much light reaches the sensor and how the image looks.
The three variables:
- Aperture (f-stop) — the size of the lens opening. Larger opening = lower f-number = more light.
- Shutter Speed — how long the sensor is exposed. Longer = more light; also controls motion blur.
- ISO — sensor sensitivity. Higher ISO = brighter image; also increases digital noise.
Exposure Value (EV) formula:
EV = log₂(f² / t)
Where f = f-number and t = shutter speed in seconds.
Relative EV adjustment:
ΔEV = log₂(f₁² / f₂²) = 2 × log₂(f₁ / f₂) (for aperture changes)
ΔEV = log₂(t₂ / t₁) (for shutter speed changes)
ΔEV = log₂(ISO₂ / ISO₁) (for ISO changes)
One stop of light means exactly doubling or halving the exposure:
- Aperture: f/2.8 → f/4 = −1 stop (half the light)
- Shutter: 1/250s → 1/500s = −1 stop
- ISO: 800 → 1600 = +1 stop
Standard full f-stop scale: f/1 · f/1.4 · f/2 · f/2.8 · f/4 · f/5.6 · f/8 · f/11 · f/16 · f/22 · f/32
Worked example: Current settings: f/4, 1/250s, ISO 400. You want to switch to f/8 (depth of field). f/4 → f/8 = −2 stops (4× less light). To compensate: slow shutter from 1/250s → 1/60s (+2 stops), or raise ISO 400 → 1600 (+2 stops), or combine both changes.
Creative trade-offs:
- Wide aperture (f/1.8–f/2.8): blurry background (bokeh) — portraits
- Fast shutter (1/1000s+): freeze motion — sports, wildlife
- Low ISO (100–200): maximum image quality — landscapes on a tripod