The Exposure Triangle
Photography exposure is controlled by three interdependent settings: aperture, shutter speed, and ISO. When you change one, you must adjust at least one other to maintain the same exposure level.
Understanding Each Setting
| Setting | Controls | Trade-off |
|---|---|---|
| Aperture | Depth of field | Wide (f/1.4) = blurry background |
| Shutter Speed | Motion blur | Fast (1/1000) = freeze action |
| ISO | Sensor sensitivity | High = more noise/grain |
Full Stop Aperture Scale
| f-stop | Light | Depth of Field |
|---|---|---|
| f/1.4 | Most light | Very shallow |
| f/2.8 | 2 stops less | Shallow |
| f/5.6 | 4 stops less | Moderate |
| f/11 | 6 stops less | Deep |
| f/22 | 8 stops less | Very deep |
Recommended Settings by Subject
| Subject | Aperture | Shutter |
|---|---|---|
| Portrait | f/1.8-f/4 | 1/125+ |
| Landscape | f/8-f/16 | Any (tripod) |
| Sports | f/2.8-f/5.6 | 1/500+ |
| Street | f/5.6-f/8 | 1/250+ |
| Night | f/1.4-f/2.8 | 1/30-30sec |
Exposure Tips
- Sunny 16 Rule: On a sunny day, set f/16 and shutter speed = 1/ISO
- Minimum handheld: Shutter speed should be at least 1/focal length
- Sweet spot: Most lenses are sharpest at f/5.6-f/8
- Low light: Open aperture first, then raise ISO
- High ISO: Modern cameras handle ISO 1600-3200 well
- Bracketing: Take multiple exposures for challenging light
EV (Exposure Value) Reference
- EV -2: Night sky
- EV 4: Indoor, artificial light
- EV 8: Overcast day
- EV 12: Cloudy bright
- EV 15: Sunny day
- EV 16: Bright sun on sand/snow