1. What is the Lens Image Distance Formula?

The lens image distance formula calculates where an image will be formed by a lens based on the focal length of the lens and the object distance. This is particularly important for designing corrective glasses.

2. How Does the Calculator Work?

The calculator uses the lens formula:

Where:

• \( di \) — Image distance (meters)
• \( f \) — Focal length of the lens (meters)
• \( do \) — Object distance (meters)

Explanation: The formula shows the relationship between the focal length of a lens, the object distance, and where the image will be formed.

3. Importance of Image Distance Calculation

Details: Calculating image distance is crucial for designing corrective lenses that properly focus light on the retina for clear vision.

4. Using the Calculator

Tips: Enter focal length and object distance in meters. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What does a negative image distance mean?
A: A negative value indicates the image is virtual (formed on the same side as the object), which is common for corrective lenses.

Q2: How does this relate to eyeglass prescriptions?
A: The focal length is related to the lens power (P = 1/f). This calculation helps determine where light will focus through the lens.

Q3: What's a typical focal length for glasses?
A: For a -2.00 diopter lens, f = -0.5m. For +3.00 diopter, f = +0.33m.

Q4: Why is object distance important?
A: For glasses, typical object distances are considered to be at infinity (for distance vision) or about 0.4m (for reading).

Q5: How does this apply to bifocals?
A: Bifocals have different focal lengths for distance and near vision, requiring different image distance calculations.