Equivalent Aperture Calculator

Calculate the equivalent aperture of a lens when mounted on different camera formats

Input Parameters

Calculation Results

Equivalent Aperture

Focal Length: 0 mm

Aperture F-Number: 0

Equivalent Aperture: 0 mm

Relative Light Gathering: 0 ×

Calculation Formula

Equivalent F-number = F-number × √(Sensor Area / Reference Area)

Where:
- F-number: The aperture f-number of the lens
- Sensor Area: Sensor width × Sensor height
- Reference Area: 36 mm × 24 mm (standard 35mm full-frame sensor)

Equivalent Aperture Calculator Calculator Usage Guide

Learn how to use the Equivalent Aperture Calculator and understand lens performance across different camera formats

How to Use This Calculator

  1. Enter the Focal Length of your lens in millimeters (mm).
  2. Enter the Aperture F-Number (f/ value) of your lens, as indicated on the lens or camera settings.
  3. Enter the Sensor Width and Sensor Height of your camera's sensor in millimeters. These can typically be found in your camera's specifications.
  4. Click the Calculate button to see the equivalent aperture and relative light gathering.

Understanding Equivalent Aperture

Equivalent aperture allows you to compare the light-gathering ability of lenses across different camera formats. A lens with the same focal length and aperture value will have a different effective aperture (and thus brightness) when used on cameras with different sensor sizes.

The calculation uses the formula:

Equivalent F-number = F-number × √(Sensor Area / Reference Area)

Example Usage

Suppose you have a 50mm f/1.8 lens on a full-frame camera (36mm × 24mm sensor). If you want to know how this lens performs on a crop sensor camera with a 22mm × 15mm sensor:

  1. Focal Length: 50 mm
  2. Aperture F-Number: 1.8
  3. Sensor Width: 22 mm
  4. Sensor Height: 15 mm

With these inputs, the calculator will show that the lens has an equivalent aperture of approximately f/2.9 on the crop sensor, making it less bright than on the full-frame camera.