Focal Length Calculator

Focal Length Formula:

\[ Focal\ Length = \frac{Sensor\ Width \times Working\ Distance}{Object\ Width} \]

Focal Length:

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1. What is Focal Length?

Focal length is the distance between the lens and the image sensor when the subject is in focus, usually stated in millimeters. It determines the angle of view and magnification of the lens.

2. How Does the Calculator Work?

The calculator uses the focal length formula:

\[ Focal\ Length = \frac{Sensor\ Width \times Working\ Distance}{Object\ Width} \]

Where:

\( Sensor\ Width \) — The width of the camera sensor (mm)
\( Working\ Distance \) — Distance from the lens to the object (mm)
\( Object\ Width \) — The width of the object being photographed (mm)

Explanation: This formula calculates the required focal length to capture an object of a specific width at a given working distance using a camera with a known sensor size.

3. Importance of Focal Length Calculation

Details: Calculating the correct focal length is essential for achieving the desired field of view in photography and videography. It helps photographers and cinematographers select the appropriate lens for specific shooting scenarios.

4. Using the Calculator

Tips: Enter the sensor width in mm, working distance in mm, and object width in mm. All values must be valid positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is sensor width and where can I find it?
A: Sensor width is the physical width of your camera's image sensor. You can typically find this specification in your camera's manual or manufacturer's website.

Q2: How does focal length affect my images?
A: Shorter focal lengths provide wider angles of view, while longer focal lengths provide narrower angles of view and greater magnification.

Q3: Can I use this calculator for different units?
A: The calculator is designed for millimeters. If you have measurements in other units, convert them to millimeters first for accurate results.

Q4: Does this formula work for all types of lenses?
A: This formula provides a good approximation for most standard lenses but may not be as accurate for specialized lenses like fisheye or telephoto.

Q5: How precise is this calculation?
A: The calculation provides a theoretical focal length. Real-world results may vary slightly due to lens design characteristics and manufacturing tolerances.