When it comes to photography, understanding exposure is crucial for capturing the perfect shot. Exposure refers to the amount of light that enters your camera and hits the film or sensor. To achieve the ideal exposure, you need to adjust three key camera settings: aperture, shutter speed, and ISO sensitivity. In this comprehensive guide, we’ll explore exposure in-depth and learn how to calculate it accurately.
Use our Exposure Calculator to quickly determine the perfect settings for your photography needs.
Exposure Calculator
What is Exposure Value (EV)?
Exposure value (EV) is a numerical representation of the lighting conditions in a scene. It ranges from positive values for bright situations to negative values for low-light conditions. Achieving the right EV for your shot is essential to ensure your subject is well-lit and the details are captured correctly.
Factors Affecting Exposure Value
- Aperture Opening: The aperture, measured in f-stops (e.g., f/2.8 or f/16), determines how much light enters the camera. A larger aperture allows more light and affects depth of field.
- Shutter Speed: Shutter speed controls the duration of exposure. Faster shutter speeds limit light intake, while slower speeds capture more light over time.
- ISO Sensitivity: ISO sensitivity measures the camera’s sensor’s response to light. Lower ISO values require more light for proper exposure, while higher ISO values increase sensitivity but may introduce noise.
Calculating Exposure Value
The exposure value (EV) can be calculated using the following formula:
EV = log2(100 * (aperture^2) / (ISO * shutter speed))
- EV: Exposure value
- aperture: Aperture value (e.g., f/2.8)
- ISO: ISO sensitivity (e.g., ISO 200)
- shutter speed: Shutter speed in seconds
A positive EV (e.g., EV+15) is suitable for well-lit conditions, while a negative EV (e.g., EV-7) is ideal for low-light situations.
Sample Calculation
Let’s say you want to photograph a rainbow on a cloudy day with an ISO sensitivity of 200. You set your aperture to f/8 and your shutter speed to 1/500 seconds. Using the EV formula:
EV = log2(100 * (8^2) / (200 * 1/500))
EV ≈ 14
With an EV of approximately 14, your camera settings are suitable for capturing the rainbow under hazy sunlight.
| EV | Type of Lighting Situation |
|---|---|
| -7 | Deep star field or the Milky Way. |
| -6 | Night under starlight only or the Aurora Borealis. |
| -5 | Night under crescent moon or the Aurora Borealis. |
| -4 | Night under half moon, or a meteor shower (with long exposure duration). |
| -3 | Night under full moon and away from city lights. |
| -2 | Night snowscape under full moon and away from city lights. |
| -1 | Start (sunrise) or end (sunset) of the “blue hour” (outdoors) or dim ambient lighting (indoors). |
| 0 | Dim ambient artificial lighting. |
| 1 | Distant view of a lit skyline. |
| 2 | Under lightning (with time exposure) or a total lunar eclipse. |
| 3 | Fireworks (with time exposure). |
| 4 | Candle-lit close-ups, Christmas lights, floodlight buildings, fountains, or bright street lamps. |
| 5 | Home interiors at night, fairs, and amusement parks. |
| 6 | Brightly lit home interiors at night, fairs, and amusement parks. Bottom of a rainforest canopy, or along brightly-lit nighttime streets. |
| 7 | Floodlit indoor sports areas or stadiums, and stage shows, including circuses. Store windows, campfires, bonfires, ice shows. |
| 8 | Floodlit indoor sports areas or stadiums, and interiors with bright fluorescent. |
| 9 | Landscapes, city skylines 10 minutes after sunset, neon lights. |
| 10 | Landscapes and skylines immediately after sunset, capturing a crescent moon using a long lens. |
| 11 | Sunsets. Subject to deep shade. |
| 12 | Open shade or heavy overcast, capturing half moon using a long lens. |
| 13 | Cloudy-bright light (no shadows), capturing gibbous moon using a long lens. |
| 14 | Weak hazy sun, rainbows (soft shadows), capturing the full moon using a long lens. |
| 15 | Bright or hazy sun, clear sky (distinct shadows). |
| 16 | Bright daylight on sand or snow (distinct shadows). |
| 17-19 | Very bright artificial lighting. |
| 20+ | Extremely bright artificial lighting, telescopic view of the sun. |
Frequently Asked Questions
What is exposure value (EV) in photography?
Exposure value (EV) represents the lighting conditions in a scene and helps determine the correct camera settings for optimal exposure.
How do aperture, shutter speed, and ISO sensitivity affect exposure?
Aperture controls light intake, shutter speed manages exposure duration, and ISO sensitivity affects the camera’s response to light.
How can I calculate exposure value (EV) for my camera settings?
You can calculate EV using the formula: EV = log2(100 * (aperture^2) / (ISO * shutter speed)). Alternatively, use an exposure calculator for quick results.
Understanding exposure and how to calculate it is essential for achieving stunning photographs. With the right EV and camera settings, you can capture the beauty of any scene, from a vibrant sunset to the mesmerizing Milky Way.