Exposure Calculator
Calculate exposure value (EV) from your camera settings. Understand the relationship between aperture, shutter speed, and ISO, and find equivalent exposure settings.
Enter as 1/125 = 125
How to Use This Calculator
- Enter your camera settings: aperture (f-stop), shutter speed (as 1/125 = enter 125), and ISO.
- The calculator displays the exposure value (EV) for your settings.
- Review the equivalent exposure settings shown for one stop brighter and one stop darker.
- Use these equivalents to adjust your settings while maintaining the same exposure level.
Exposure Value Formula
Exposure value combines aperture, shutter speed, and ISO into a single number:
Example: f/2.8, 1/125s, ISO 400: EV = log₂(2.8² ÷ 125) + log₂(400 ÷ 100) = log₂(0.0627) + log₂(4) = -3.99 + 2 = -1.99 EV.
Full Description
Exposure value (EV) is a standardized way to express camera exposure settings, combining the three elements of the exposure triangle—aperture, shutter speed, and ISO—into a single number. This allows photographers to compare different exposure combinations and understand how to achieve equivalent exposures using different settings.
The exposure triangle is fundamental to photography: aperture controls depth of field and light, shutter speed controls motion blur and light, and ISO controls sensor sensitivity and noise. All three work together to determine the final exposure. Understanding how to balance these settings is key to creative control.
This calculator helps you understand the relationship between these settings and find equivalent exposures. For example, if you want to freeze motion (faster shutter) but maintain the same exposure, you can open the aperture or increase ISO. The calculator shows you exactly how to make these adjustments while keeping exposure constant.
Frequently Asked Questions
What is exposure value (EV)?
Exposure value is a numerical representation of camera exposure settings that combines aperture, shutter speed, and ISO into a single number. It allows photographers to compare different exposure combinations and understand equivalent settings.
What are equivalent exposure settings?
Equivalent exposures produce the same image brightness but use different combinations of aperture, shutter speed, and ISO. For example, f/2.8 at 1/125s ISO 400 is equivalent to f/4 at 1/60s ISO 400—both let in the same amount of light.
What is a "stop" in photography?
A stop is a doubling or halving of light. Each stop change doubles or halves the exposure. Changing aperture from f/2.8 to f/4 is one stop darker (half the light). Changing shutter from 1/125s to 1/250s is one stop darker. Changing ISO from 400 to 800 is one stop brighter.
How do I use EV for exposure compensation?
EV helps you understand how to adjust settings while maintaining the same exposure. If you want one stop brighter, you can open aperture one stop, slow shutter one stop, or double ISO. The calculator shows equivalent settings for one stop brighter or darker.