Photography Exposure Value (EV) Calculator
指导
Photography Exposure Value (EV) Calculator
Dial in the exposure triangle without leaving the browser. Pick any two of aperture, shutter speed, and ISO and the calculator solves for the third, displays the resulting EV, and lays out every equivalent combination at the same exposure. A built-in scene reference based on the classic Sunny 16 rule helps you start from real-world lighting instead of guessing.
如何使用
- Choose what you want to Solve For — aperture, shutter speed, ISO, or just EV.
- Set the two settings you already know from the standard 1/3-stop dropdowns.
- 选择一个 scene preset (Sunny 16, overcast, indoor, moonlight, etc.) or enter a manual target EV at ISO 100.
- Read the result and the EV summary, then explore equivalent exposure combinations to balance depth of field, motion blur, and noise.
特征
- Solve for any variable – pick aperture, shutter, ISO, or compute EV directly from all three.
- 1/3-stop precision – aperture, shutter, and ISO dropdowns match real camera dial steps from f/1.0 to f/32 and 1/8000 s to 30 s.
- Scene presets – 19 lighting situations from snow at noon (EV 16) to starlight (EV -6) based on the Sunny 16 family of rules.
- Equivalent exposure table – every combination that produces the same EV, with depth-of-field and motion hints for each row.
- EV, EV100, and Light Value – three readouts in one place, with the closest matching scene called out automatically.
- 纯客户端运行 – nothing leaves your browser, instant updates as you change settings.
常问问题
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What is Exposure Value (EV)?
Exposure Value is a single number that represents a combination of aperture and shutter speed that lets the same amount of light reach the sensor. The formula is EV = log₂(N² / t), where N is the f-number and t is the shutter time in seconds. EV is measured against ISO 100 by convention; raising ISO by one stop is equivalent to adding 1 EV of brightness.
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What is the Sunny 16 rule?
The Sunny 16 rule is a meterless exposure shortcut: on a bright sunny day, set the aperture to f/16 and the shutter speed to 1 over the ISO (for example, ISO 100 and 1/100 s). That combination corresponds to roughly EV 15 at ISO 100. The same family of rules extends to cloudy, overcast, shade, and night-time scenes, each one stop apart.
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What does equivalent exposure mean?
Equivalent exposures are combinations of aperture, shutter speed, and ISO that all let in the same total amount of light, so they yield the same brightness. They are not visually identical, though: a wider aperture gives a shallower depth of field, a slower shutter shows more motion blur, and a higher ISO adds noise. Photographers swap between equivalents to bias the trade-off toward depth of field, motion, or low-light reach.
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Why does each step on a camera dial halve or double the light?
Aperture, shutter speed, and ISO are scaled in stops, which is the photographer's word for factors of two. Doubling the shutter time, opening the aperture by one full stop (for example f/8 to f/5.6), or doubling the ISO each lets in twice as much light. That base-2 relationship is what makes the EV formula a clean logarithm and why the dropdowns step in 1/3-stop increments.
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How does ISO change the calculation?
ISO does not change how much light hits the sensor; it changes how much amplification is applied to the captured signal. In the EV formula it adds a log₂(ISO/100) term, so doubling the ISO bumps the effective EV up by one. Practically, that means a higher ISO lets you shoot at a smaller aperture or faster shutter for the same scene, at the cost of more digital noise.
