Exposure Calculator
Calculate the proper exposure settings based on ISO, aperture, and shutter speed. Find the perfect exposure triangle for your photography.
Calculate Your Exposure Calculator
Understanding Exposure in Photography
In photography, exposure refers to the amount of light that reaches your camera's sensor, creating the image. Proper exposure is the foundation of a good photograph, determining whether your image is too dark (underexposed), too bright (overexposed), or just right.
The exposure triangle consists of three essential elements that work together to control the exposure: aperture, shutter speed, and ISO. Understanding how these elements interact allows photographers to achieve the right exposure while making creative decisions about depth of field, motion blur, and image noise.
The Exposure Triangle Explained
Aperture (f-stop)
Aperture controls the size of the opening in your lens through which light passes. It's measured in f-stops (like f/2.8, f/4, f/5.6, etc.). A lower f-number means a larger aperture opening, allowing more light in and creating a shallower depth of field (more background blur). A higher f-number means a smaller aperture, letting in less light but providing greater depth of field (more of the scene in focus).
Shutter Speed
Shutter speed determines how long your camera's sensor is exposed to light. It's measured in seconds or fractions of a second (like 1/1000, 1/250, 1/60, etc.). Faster shutter speeds (like 1/1000) freeze motion and let in less light. Slower shutter speeds (like 1/30 or longer) allow more light but may introduce motion blur if the subject or camera moves during exposure.
ISO
ISO measures your camera sensor's sensitivity to light. Lower ISO values (like 100 or 200) are less sensitive to light, producing less noise but requiring more light from aperture or shutter speed. Higher ISO values (like 1600 or 3200) are more sensitive, allowing you to shoot in darker conditions, but often introduce more noise or grain to the image.
Understanding Exposure Value (EV)
Exposure Value (EV) is a number that represents a combination of aperture, shutter speed, and ISO that produces a correctly exposed image under specific lighting conditions. The EV scale typically ranges from -6 to 20, with lower values representing darker scenes and higher values for brighter scenes.
| EV Range | Typical Lighting Conditions | Example Settings |
|---|---|---|
| -6 to -4 | Night scenes, starlit landscapes | f/2.8, 30s, ISO 1600 |
| -3 to 0 | Night urban scenes, moonlight | f/2.8, 15s, ISO 800 |
| 1 to 3 | Dawn/dusk, indoor dim lighting | f/2.8, 1/15s, ISO 400 |
| 4 to 6 | Indoor well-lit, sunset/sunrise | f/4, 1/60s, ISO 400 |
| 7 to 9 | Overcast, indoor bright lighting | f/5.6, 1/125s, ISO 200 |
| 10 to 12 | Cloudy daylight, open shade | f/8, 1/125s, ISO 100 |
| 13 to 15 | Sunny daylight, clear sky | f/11, 1/125s, ISO 100 |
| 16 to 20 | Bright sun on sand/snow, high altitude | f/16, 1/250s, ISO 100 |
How to Use This Calculator
Our Exposure Calculator offers two main functions to help you achieve perfect exposure in your photography:
Calculate EV
Use this function when you know your camera settings and want to determine the Exposure Value (EV) for a particular scene. This helps you understand the lighting conditions better and plan future shots.
- Select your aperture (f-stop)
- Choose your shutter speed
- Set your ISO value
- Click "Calculate Exposure Value"
- The calculator will show you the EV number and what lighting conditions it corresponds to
Find Settings
Use this function when you know the lighting conditions (EV) and want to determine possible camera settings. This helps you explore equivalent exposures that give the same brightness but with different creative effects.
- Set the Exposure Value (EV) based on your lighting conditions
- Choose your ISO value
- Click "Calculate Camera Settings"
- The calculator will show you multiple combinations of aperture and shutter speed that will provide correct exposure
- Choose the combination that best suits your creative vision (depth of field, motion blur, etc.)
Creative Control with Equivalent Exposures
One of the most powerful concepts in photography is that different combinations of aperture, shutter speed, and ISO can produce the same exposure (brightness) but with very different creative effects.
Aperture Priority (Control Depth of Field)
- Large aperture (small f-number like f/1.8): Creates shallow depth of field with blurred backgrounds, ideal for portraits and isolating subjects.
- Small aperture (large f-number like f/11): Creates deep depth of field with more of the scene in focus, ideal for landscapes and architecture.
Shutter Priority (Control Motion)
- Fast shutter speed (like 1/1000s): Freezes motion, ideal for sports, wildlife, and action photography.
- Slow shutter speed (like 1/15s or slower): Creates motion blur, ideal for conveying movement in waterfalls, traffic, or intentional camera movement effects.
Tips for Perfect Exposure
- Use the histogram: Many cameras show a histogram of your image's brightness. Aim for a balanced distribution without clipping (sharp peaks at the far left or right).
- Expose for the highlights: In high-contrast scenes, it's often better to preserve highlight detail (slight underexposure) as you can recover shadow detail more easily in post-processing.
- Bracket exposures: In tricky lighting, take multiple shots at different exposures (bracketing) to ensure you capture the scene properly.
- Consider metering modes: Your camera's metering system (evaluative, center-weighted, spot) affects how it reads the scene. Choose the appropriate mode for your subject.
- Use exposure compensation: If your camera consistently over or underexposes in certain situations, use exposure compensation to adjust.
- Remember the Sunny 16 rule: On a sunny day, set aperture to f/16 and shutter speed to 1/ISO (e.g., f/16, 1/100s, ISO 100) for a good starting point.
Related Calculators
Frequently Asked Questions
The exposure triangle refers to the three fundamental elements that control the exposure of a photograph: aperture, shutter speed, and ISO. Each element affects not only the brightness of the image but also other aspects of image quality:
- Aperture (f-stop): Controls the amount of light entering the lens and affects depth of field.
- Shutter Speed: Controls how long the sensor is exposed to light and affects motion blur.
- ISO: Controls the sensor's sensitivity to light and affects image noise/grain.
These three elements work together—when you adjust one, you typically need to adjust at least one other to maintain the same exposure.
Exposure Value (EV) is a number that represents a combination of aperture and shutter speed that yields the same exposure. For example, EV 15 represents a sunny day, while EV 0 might represent a night scene lit by moonlight.
EV is useful because it:
1. Provides a simple way to communicate light levels without specifying exact camera settings
2. Allows you to determine appropriate camera settings for specific lighting situations
3. Helps you find equivalent exposures (different combinations of aperture and shutter speed that produce the same brightness)
4. Makes it easier to use light meters and exposure tables
Our calculator uses EV to help you determine proper settings for various lighting conditions or to analyze the lighting in your current setup.
In photography, a "stop" is a unit of measurement that represents a doubling or halving of the amount of light. When you change exposure by one stop, you're either doubling or halving the amount of light reaching the sensor.
For each exposure element:
- Aperture: One stop is represented by standard f-stop values. Moving from f/2.8 to f/4 is one stop less light (halving). Common full stops: f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22.
- Shutter Speed: One stop means doubling or halving the time. Moving from 1/125s to 1/250s is one stop less light. Common full stops: 1s, 1/2s, 1/4s, 1/8s, 1/15s, 1/30s, 1/60s, 1/125s, 1/250s, 1/500s, 1/1000s.
- ISO: One stop means doubling or halving sensitivity. Moving from ISO 200 to ISO 400 is one stop more sensitivity. Common full stops: 100, 200, 400, 800, 1600, 3200.
Understanding stops allows you to maintain the same exposure while changing settings. For example, if you increase shutter speed by one stop (less light), you can compensate by increasing aperture by one stop (more light).
To achieve a blurred background (shallow depth of field) in your photos:
1. Use a large aperture (small f-number): Select settings like f/1.8, f/2.8, or f/4. The lower the f-number, the more background blur you'll get.
2. Use a longer focal length: Telephoto lenses (e.g., 85mm, 135mm, 200mm) create more background blur than wide-angle lenses.
3. Increase the distance between subject and background: Position your subject further away from the background elements.
4. Decrease the distance between camera and subject: Moving closer to your subject enhances the background blur effect.
Using our calculator's "Find Settings" mode, you can determine the appropriate shutter speed and ISO to combine with your chosen wide aperture to maintain proper exposure.
To freeze motion in your photographs:
1. Use a fast shutter speed: This is the most important factor. For different subjects:
- Fast-moving sports/wildlife: 1/1000s or faster
- People walking/running: 1/250s to 1/500s
- Children playing: 1/500s or faster
- General everyday scenes: 1/125s to 1/250s
2. Increase ISO if needed: If lighting conditions don't allow for fast shutter speeds, increase ISO to maintain proper exposure (accepting some noise).
3. Use a wider aperture: Open up your aperture (smaller f-number) to allow more light in while maintaining fast shutter speeds.
4. Add light: Use flash or additional lighting if the scene is too dark for fast shutter speeds.
With our calculator's "Find Settings" feature, you can determine the right aperture and ISO combinations that allow for your desired fast shutter speed.
Handling challenging lighting scenarios:
- High contrast (bright and dark areas):
- Expose for highlights and lift shadows in post-processing
- Use HDR techniques (multiple exposures combined)
- Use graduated neutral density filters - Backlit subjects:
- Use spot metering on the subject
- Overexpose slightly to properly expose the subject
- Use fill flash to illuminate the subject - Very low light:
- Use a tripod to allow longer shutter speeds
- Use a wide aperture lens (f/1.8 or wider)
- Increase ISO, balancing noise with necessary shutter speed
- Consider noise reduction in post-processing - Bright, harsh sunlight:
- Shoot during golden hours (early morning/late afternoon)
- Move subjects to open shade
- Use reflectors or fill flash to soften shadows
- Use a polarizing filter to control reflections
Use our calculator to determine baseline settings for these conditions, then adjust as needed based on creative intent and the specific challenges of the scene.
Equivalent exposure means different combinations of aperture, shutter speed, and ISO that produce the same brightness. For example, f/8 at 1/125s at ISO 100 produces the same exposure as f/5.6 at 1/250s at ISO 100.
You can use equivalent exposures creatively:
1. Control depth of field: Choose a wider aperture (smaller f-number) for background blur, compensating with faster shutter speed or lower ISO.
2. Control motion: Choose a specific shutter speed to freeze action or create motion blur, adjusting aperture and ISO to maintain exposure.
3. Control noise: Keep ISO as low as possible for the cleanest image, adjusting aperture and shutter speed accordingly.
4. Balance multiple factors: Find the sweet spot that balances depth of field, motion rendering, and image noise for your specific creative vision.
Our calculator's "Find Settings" feature shows you multiple equivalent exposure combinations, allowing you to choose the one that best achieves your creative goals.
The Sunny 16 Rule is a method for estimating proper exposure without a light meter. The basic rule states:
On a sunny day, set your aperture to f/16 and your shutter speed to 1/ISO.
For example, with ISO 100, use f/16 and 1/100s. With ISO 400, use f/16 and 1/400s.
For different lighting conditions, adjust your aperture:
- Bright sun on snow/sand: f/22
- Sunny: f/16
- Slight overcast: f/11
- Overcast: f/8
- Heavy overcast: f/5.6
- Open shade/sunset: f/4
You can also maintain f/16 and adjust shutter speed or ISO accordingly. For example, in slight overcast (normally f/11), you could keep f/16 but make shutter speed twice as long (e.g., from 1/100s to 1/50s).
The Sunny 16 Rule is a useful starting point that corresponds to specific EV values on our calculator.
Auto exposure can be fooled by several situations:
Common causes of overexposure:
1. Dark subjects/backgrounds: The camera tries to brighten them, overexposing the rest of the scene
2. Backlit scenes: The camera averages the very bright background with the darker subject
3. Bright snow or beach scenes: The camera tries to make them gray instead of white
Common causes of underexposure:
1. Very bright subjects/backgrounds: The camera darkens them, underexposing the rest
2. Spot metering on a bright area: This makes the camera expose for that spot only
3. Strong light sources in frame: The camera compensates for these bright spots
Solutions:
1. Use exposure compensation: +1 or +2 for snow/beach, -1 or -2 for bright subjects
2. Change metering mode: Spot metering for specific subjects, evaluative for balanced scenes
3. Use manual mode: Use our calculator to determine proper settings based on the scene's EV
4. Bracket exposures: Take multiple shots at different exposures to ensure one is correct
Understanding metering and using the histogram are key skills for overcoming auto exposure limitations.
ISO affects image quality primarily through noise and dynamic range:
Higher ISO Settings (e.g., 1600, 3200, 6400+):
1. Increased noise/grain: Higher ISO amplifies the signal from the sensor, but also amplifies noise, resulting in a grainier appearance.
2. Reduced dynamic range: The ability to capture detail in both highlights and shadows diminishes.
3. Decreased color accuracy: Colors may appear less vibrant and more washed out.
4. Lower contrast: The overall image may appear flatter with less distinction between tones.
Lower ISO Settings (e.g., 100, 200, 400):
1. Cleaner images: Less noise, resulting in smoother transitions and finer detail.
2. Better dynamic range: More detail preserved in highlights and shadows.
3. Richer colors: More accurate and vibrant color reproduction.
Best Practices:
- Use the lowest ISO possible for the shooting conditions
- Modern cameras perform better at high ISO than older ones
- Full-frame sensors typically handle high ISO better than crop sensors
- Consider noise reduction in post-processing for high ISO images
- Good exposure technique can sometimes allow lower ISO than you might think
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