1. What is Magnification from Focal Length?

The magnification of an optical system can be calculated by dividing the focal length of the objective by the focal length of the eyepiece. This simple formula provides the angular magnification of the system.

2. How Does the Calculator Work?

The calculator uses the magnification formula:

Where:

• \( mag \) — Magnification (dimensionless)
• \( f_{objective} \) — Focal length of the objective (mm)
• \( f_{eyepiece} \) — Focal length of the eyepiece (mm)

Explanation: The longer the objective focal length or the shorter the eyepiece focal length, the higher the magnification.

3. Importance of Magnification Calculation

Details: Understanding magnification is crucial for designing optical systems like telescopes and microscopes, and for selecting appropriate eyepieces for desired viewing experiences.

4. Using the Calculator

Tips: Enter both focal lengths in millimeters. Both values must be positive numbers greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical magnification range for telescopes?
A: Most telescopes perform well between 20× and 50× per inch of aperture, with practical limits set by atmospheric conditions.

Q2: Can I use any eyepiece with any objective?
A: While physically possible, extremely high magnifications often result in poor image quality due to optical limitations.

Q3: How does magnification affect field of view?
A: Higher magnification typically results in a narrower field of view and reduced brightness.

Q4: What is the useful maximum magnification?
A: As a rule of thumb, maximum useful magnification is about 2× per mm of aperture diameter (or 50× per inch).

Q5: Does this formula work for all optical systems?
A: This formula works for simple telescopes and microscopes. More complex systems may require additional calculations.