1. What is the Lens Formula?

The lens formula is a fundamental equation in optics that relates the focal length of a lens to the object distance and image distance. It provides a mathematical relationship for calculating how light rays converge or diverge through a lens.

2. How Does the Calculator Work?

The calculator uses the lens formula:

Where:

• \( FL \) — Focal length (mm)
• \( o \) — Object distance (mm)
• \( i \) — Image distance (mm)

Explanation: The formula calculates the focal length based on the reciprocal relationship between object distance, image distance, and focal length.

3. Importance of Focal Length Calculation

Details: Accurate focal length calculation is crucial for lens design, photography, microscopy, and various optical applications where precise focusing is required.

4. Using the Calculator

Tips: Enter object distance and image distance in millimeters. Both values must be positive numbers greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is focal length?
A: Focal length is the distance between the lens and the image sensor when the subject is in focus, usually measured in millimeters.

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

Q3: What are typical focal length values?
A: Focal lengths vary widely from a few millimeters (wide-angle) to several hundred millimeters (telephoto) depending on the lens type and application.

Q4: Are there limitations to this formula?
A: This formula works well for thin lenses in air. For thick lenses or different media, more complex calculations are needed.

Q5: Can this calculator be used for concave lenses?
A: Yes, but note that for concave lenses, the focal length is negative, indicating a diverging lens.