Exposure Value Calculator

The Exposure Value Calculator helps photographers evaluate the light exposure settings of their camera by combining shutter speed and aperture into a single number called EV, or Exposure Value. This number simplifies the process of adjusting lighting in photography, whether indoors or outdoors, in bright or low-light conditions.

By using this calculator, users can easily determine if their settings will lead to underexposure or overexposure, enabling precise control over the brightness of the final image. It’s a powerful and efficient tool used in photography, cinematography, and visual media planning.

Formula of Exposure Value Calculator

Exposure Value (EV) = log₂(N² / t)

Where:

• EV is the Exposure Value
• N is the f-number (aperture setting)
• t is the exposure time (shutter speed in seconds)
• log₂ means base-2 logarithm

Expanded version:
EV = log₂(N²) − log₂(t)

This formula shows that increasing the aperture number (smaller opening) or reducing the exposure time (faster shutter) raises the EV, resulting in a darker image. On the other hand, a larger aperture or slower shutter speed lowers the EV, leading to a brighter image.

With ISO correction:
EV₁₀₀ = EV + log₂(ISO / 100)

Where:

• EV₁₀₀ is the ISO-normalized exposure value
• ISO is the sensor sensitivity (e.g., 100, 200, 400)

This adjustment helps compare different ISO settings for consistent light exposure.

Reference Table for Fast Understanding

This table helps photographers pick EV settings faster without doing the math every time.

Example of Exposure Value Calculator

Let’s say a photographer uses an aperture of f/5.6 and a shutter speed of 1/125 seconds.

First, calculate EV:

EV = log₂(5.6² / (1/125))
EV = log₂(31.36 × 125) = log₂(3920) ≈ 11.9

If the ISO is set to 200, then the adjusted EV is:

EV₁₀₀ = 11.9 + log₂(200 / 100)
EV₁₀₀ = 11.9 + log₂(2) = 11.9 + 1 = 12.9

This means the settings correspond to an EV of 12.9 when normalized to ISO 100, suitable for bright daylight shots.

Most Common FAQs