Focal Length Calculator

The Focal Length Calculator helps users determine the angle of view, field of view width, crop factor, and full-frame equivalent focal length based on camera sensor size, focal length, and distance to the subject.

Use Our Focal Length Calculator

Step-by-Step Guide to Using the Focal Length Calculator

Step 1: Select Camera Sensor Size

Begin by choosing the appropriate camera sensor size. This can be done using the first input field labeled Camera Sensor Size. Click on the dropdown menu to see the available options. You can select from the following choices:

  • Full Frame (36 x 24mm)
  • APS-C Canon (22.3 x 14.9mm)
  • APS-C Nikon/Sony (23.5 x 15.6mm)
  • Micro Four Thirds (17.3 x 13mm)
  • 1-inch Type (13.2 x 8.8mm)

Choose the option that matches your camera’s sensor size.

Step 2: Enter Focal Length

In the field labeled Focal Length (mm), enter the focal length of the lens you are using. This should be a numeric value between 1 and 2000, inclusive. Ensure that this information is accurate as it impacts the calculations of the angle of view and field of view width.

Step 3: Enter Distance to Subject

Next, input the distance from the camera to the subject in the field titled Distance to Subject (meters). This value should be a number between 0.1 and 10,000, inclusive. Knowing the correct distance helps in calculating the field of view width effectively.

Step 4: Review Calculated Results

After entering all the required data, the calculator will automatically compute several important results, which include:

  • Angle of View: Displays the angle of view based on the sensor width and focal length. It will appear with a suffix of “°” to denote degrees.
  • Field of View Width: This result shows the width of the field of view expressed in meters, calculated using the entered distance and angle of view.
  • Crop Factor: Indicates the crop factor relative to a full-frame sensor. It is calculated as the ratio of 43.3 divided by your chosen sensor width, with a prefix of “×”.
  • Full Frame Equivalent Focal Length: This result gives you the equivalent focal length for a full-frame camera, computed by multiplying the entered focal length by the crop factor. The result will be followed by “mm” indicating millimeters.

Use these calculations to better understand how your camera setup will capture a scene and to make informed decisions on lens and camera settings.