When to use this calculator
Find signed lateral magnification from object and image distances. Negative magnification indicates an inverted image under the stated thin-lens convention.
Explore the optics & quantum relationships calculators for other questions in this topic. For a related calculation, use the Lens Power Calculator: Convert a lens focal length in metres into optical power.
PUTTING IT INTO PRACTICE
Lens Magnification: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| Signed image distance | 20 |
| Positive real object distance | 10 |
| Result | -2 × |
- Check the input labels and enter the example values above.
- Apply the relationship: Lateral magnification = −image distance/object distance.
- The result is -2 ×, rounded for display.
How to interpret your result
Negative magnification indicates an inverted image under the stated thin-lens convention.
Use the stated sign convention for lenses and angles measured to the normal for refraction. Vacuum wavelength differs from wavelength inside a material. These models do not account for every optical aberration or material response.
Frequently asked questions
Why can a refracted-angle calculation have no real result?
When Snell’s-law sine exceeds one, the ideal ray model predicts total internal reflection rather than a real transmitted angle.
When is the lens magnification calculator useful?
Find signed lateral magnification from object and image distances. Negative magnification indicates an inverted image under the stated thin-lens convention.
How do I use the lens magnification calculator?
Enter signed image distance, positive real object distance. The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Lateral magnification = −image distance/object distance.
What should I check before using the result?
Negative magnification indicates an inverted image under the stated thin-lens convention.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
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