1. What is a Lens Diffraction Calculator?

Definition: This calculator determines the diffraction angle of light passing through a circular aperture using the Rayleigh criterion.

Purpose: It helps photographers, astronomers, and optical engineers understand the limitations of lens resolution due to diffraction.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \theta \) — Diffraction angle (radians)
• \( \lambda \) — Wavelength of light (meters)
• \( D \) — Diameter of the aperture (meters)
• 1.22 — Constant derived from first zero of Bessel function

Explanation: The angle increases with longer wavelengths and decreases with larger apertures.

3. Importance of Diffraction Calculation

Details: Understanding diffraction helps optimize lens performance, especially in photography (choosing aperture) and telescope design.

4. Using the Calculator

Tips:

• Enter wavelength in meters (550nm = 0.00000055m default)
• Enter aperture diameter in meters (e.g., 0.05m for 50mm lens)
• Both values must be > 0

5. Frequently Asked Questions (FAQ)

Q1: What's a typical visible light wavelength?
A: Visible light ranges from ~400-700nm (0.0000004-0.0000007m). 550nm (green) is often used as average.

Q2: How does aperture affect diffraction?
A: Smaller apertures (higher f-numbers) produce larger diffraction angles, reducing image sharpness.

Q3: When does diffraction become noticeable?
A: Typically when the Airy disk becomes larger than the pixel size or circle of confusion.

Q4: Can diffraction be eliminated?
A: No, it's a fundamental wave phenomenon, but its impact can be minimized with larger apertures.

Q5: How is this related to the Rayleigh criterion?
A: This angle represents the minimum angular separation where two point sources can be resolved.