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Thin Lens Focal Length Calculator
Calculate focal length, image distance or magnification using the thin lens equation.
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Focal
Compare Your Options And Get Clear Answers
Calculate focal length, image distance or magnification using the thin lens equation.
Thin Lens Focal Length Estimator
Enter your numbers below for an instant estimate.
0
💡 Tip: 1/f = 1/do + 1/di.
How It Works
Key concepts behind this calculator
1
Enter Values
Fill in each field with your own numbers.
2
Calculate
Results update as you change the inputs.
3
Review
Read the breakdown and the explanation.
4
Adjust
Change values to compare scenarios.
Quick Reference Guide
Thin Quick Guide
Typical values for reference.
| Object cm | Image cm | Spare | f cm |
|---|---|---|---|
| 20 | 20 | – | 10.00 |
| 30 | 15 | – | 10.00 |
| 50 | 25 | – | 16.67 |
| 100 | 10 | – | 9.09 |
| Rule of Thumb | Check inputs | Use as a guide | Round sensibly |
Common Questions
Thin Lens Focal Calculator FAQ
Answers to common questions about this calculator.
Thin lens.
It gives a quick estimate of thin lens focal length from the values you enter.
No. It is a planning estimate, so check important figures with a professional or official source.
Yes. Edit any field and the result updates when you calculate.