Exposure Calculator
Calculate camera exposure values and settings using the exposure triangle.
Enter your aperture, shutter speed, and ISO to compute the Exposure Value (EV) for any lighting condition.
Exposure Calculator
Calculate camera exposure values and settings using the exposure triangle.
Examples
Click any button below to load a real-world scenario into the calculator.
| Settings | Scene EV | Scenario |
|---|---|---|
| f/8 · 1/125 s (0.008 s) · ISO 100 · EC 0 | EV ≈ 13 | Bright outdoor daylight |
| f/2.8 · 1/60 s (0.0167 s) · ISO 400 · EC 0 | EV ≈ 11 | Indoor window light |
| f/1.4 · 1/30 s (0.0333 s) · ISO 1600 · EC 0 | EV ≈ 10 | Dimly lit room |
| f/5.6 · 1/500 s (0.002 s) · ISO 200 · EC +1 | EV ≈ 16 | Overcast outdoor scene with +1 compensation |
About the Exposure Calculator
The Exposure Calculator is a powerful tool for photographers of all skill levels who want to master the art of controlling light in their images. At the heart of photography lies the concept of exposure — the amount of light that reaches your camera sensor or film during a shot. Too much light produces an overexposed, washed-out image; too little creates an underexposed, dark result. Achieving the perfect exposure requires balancing three interdependent camera settings known as the exposure triangle: aperture, shutter speed, and ISO sensitivity.
Aperture refers to the size of the opening in your lens through which light passes. It is expressed as an f-stop number such as f/1.4, f/2.8, f/8, or f/16. A lower f-stop number means a wider opening and more light entering the camera, while a higher f-stop means a smaller opening and less light. Aperture also controls depth of field — wide apertures produce a shallow depth of field with a blurred background, ideal for portraits, while narrow apertures give a deep depth of field with everything in sharp focus, perfect for landscapes.
Shutter speed determines how long the sensor is exposed to light. Fast shutter speeds (e.g., 1/1000s) freeze motion and reduce the risk of camera shake. Slow shutter speeds (e.g., 1/15s or longer) allow more light in and can create motion blur effects for flowing water or light trails. Shutter speed and aperture work together reciprocally: doubling the shutter speed halves the exposure, while opening the aperture one stop doubles it.
ISO sensitivity measures how responsive your sensor is to light. Low ISO values (100–200) produce clean, low-noise images and are best used in bright conditions. Higher ISO values (800–3200 or more) allow shooting in dim environments but introduce digital noise or grain into the image. Modern cameras handle high ISO remarkably well, but minimizing noise is still a consideration.
The Exposure Value (EV) is a standardized number that combines these three settings into a single measure of light. For a given ISO 100 baseline, EV = log₂(N²/t) where N is the aperture f-stop and t is the shutter speed in seconds. This calculator extends the formula to include your actual ISO and any exposure compensation you apply, giving you the true scene EV. EV values typically range from about −6 (extremely dark) to 20 (direct sunlight on snow). By understanding EV, photographers can quickly translate lighting conditions into appropriate camera settings and maintain consistent results across different scenes.
How to Use This Calculator
- Enter your lens aperture as an f-stop number (e.g., 2.8 for f/2.8 or 8 for f/8).
- Enter the shutter speed in seconds as a decimal (e.g., 0.008 for 1/125 s, 0.0167 for 1/60 s).
- Enter your camera's ISO sensitivity (e.g., 100, 400, 1600).
- Optionally enter an exposure compensation value in EV stops (positive to brighten, negative to darken).
- Click 'Calculate Exposure' to see the computed Scene EV and ISO-100 baseline EV.
Frequently Asked Questions
What is Exposure Value (EV)?
Exposure Value is a dimensionless number that combines aperture, shutter speed, and ISO into a single measure of exposure. At ISO 100, EV = log₂(N²/t) where N is the f-stop and t is the shutter speed in seconds. Each whole EV step represents a doubling or halving of the total light captured.
How do aperture, shutter speed, and ISO relate to each other?
They form the exposure triangle. Widening the aperture by one stop, doubling the shutter speed, or halving the ISO each increase exposure by one stop (one EV). You can trade them freely while keeping the same total exposure, though each change has creative side effects on depth of field, motion blur, and image noise.
What shutter speed should I enter?
Enter the shutter speed as a decimal fraction of a second. For example, 1/125 s becomes 0.008, 1/60 s becomes approximately 0.0167, and 1/500 s becomes 0.002. Longer exposures like 2 seconds are simply entered as 2.
What does the EV at ISO 100 mean?
The ISO-100 EV strips out the ISO contribution and tells you how much light is entering the lens for a given aperture and shutter speed. It is useful for comparing exposures across cameras with different ISO ranges and for referencing standard EV tables used in traditional light metering.
When should I use exposure compensation?
Use positive compensation (+1 or +2 EV) to brighten images of predominantly white or bright subjects like snow, as camera meters tend to underexpose them. Use negative compensation (−1 or −2 EV) for predominantly dark scenes. The calculator adds your EC value to the final scene EV.
Why does my calculated EV differ from my camera's meter reading?
Camera meters measure reflected light from the scene, while this calculator computes EV purely from your manually entered settings. Meter readings can also vary depending on metering mode (spot, center-weighted, evaluative) and the actual brightness distribution of your scene.