Calculator
Use any supported method below. The calculator area uses a three-column large layout, two-column medium layout, and one-column mobile layout.
Example Data Table
| Case | Given Data | Formula | Result |
|---|---|---|---|
| Single lens | f = 0.50 m | P = 1 / f | 2.00 D |
| Short focal lens | f = 250 mm | P = 1 / f | 4.00 D |
| Contact combination | P1 = 2 D, P2 = 1.5 D | P = P1 + P2 | 3.50 D |
| Separated lenses | P1 = 3 D, P2 = 2 D, d = 0.02 m | P = P1 + P2 - dP1P2 | 4.88 D |
| Refracting surface | n1 = 1.0, n2 = 1.5, R = 0.10 m | P = (n2 - n1) / R | 5.00 D |
Formula Used
1) Optical power from focal length: P = 1 / f, where f is in meters and P is in diopters.
2) Focal length from optical power: f = 1 / P.
3) Thin lens with real positive distances: P = 1/u + 1/v.
4) Thin lenses in contact: Ptotal = P1 + P2 + P3.
5) Thin lenses separated by distance d: Peq = P1 + P2 - dP1P2, with d in meters.
6) Single refracting surface: P = (n2 - n1) / R.
7) Thick lensmaker equation: P = (n - 1)[(1/R1) - (1/R2) + ((n - 1)t)/(nR1R2)].
Use signed radii in the lensmaker mode. Positive and negative results represent converging and diverging behavior respectively.
How to Use This Calculator
- Select the required calculation mode.
- Enter the known optical quantities and choose proper units.
- Press the calculate button to show the result above the form.
- Review power, focal length, lens classification, and graph output.
- Download the current result as CSV or PDF when needed.
- Compare your setup with the example table for quick verification.
FAQs
1) What is one diopter?
One diopter equals the reciprocal of focal length in meters. A 1 m focal length lens has a power of 1 D.
2) What does a negative diopter mean?
A negative diopter means the element is diverging. It spreads incoming rays and has a negative focal length under standard sign conventions.
3) Why does unit conversion matter here?
Diopter formulas assume meters. If you enter millimeters or centimeters, the calculator converts them first to avoid scaling mistakes.
4) Can I combine multiple thin lenses?
Yes. Use the contact mode for lenses touching each other, or the separated mode when a physical gap exists between lenses.
5) When should I use the lensmaker mode?
Use lensmaker mode when you know lens refractive index, both surface radii, and center thickness. It is useful during optical design and estimation.
6) Does this tool support refracting surfaces?
Yes. The refracting surface mode computes power from refractive indices and radius of curvature, which is common in geometrical optics work.
7) Why is the graph helpful?
The graph shows how optical power changes with focal length. It helps visualize nonlinear behavior and quickly spot unusually strong or weak lenses.
8) Is this suitable for engineering study?
Yes. It is useful for optics coursework, preliminary design checks, lab exercises, and quick comparison of common lens-power scenarios.