Examples
Examples
Try the starting example
- First focal length (mm)
- 100
- Second focal length (mm)
- 200
- Lens separation (mm)
- 50
- Equivalent focal length (mm)
- 80
- Equivalent optical power (diopters)
- 12.5
Try another scenario
- First focal length (mm)
- 110.00000000000001
- Second focal length (mm)
- 200
- Lens separation (mm)
- 50
- Equivalent focal length (mm)
- 84.615385
- Equivalent optical power (diopters)
- 11.818182
Calculation method
Calculation method
Equivalent focal length (mm)
Equivalent power=1/f1+1/f2-separation/(f1f2), all in mm.
Equivalent optical power (diopters)
Equivalent power=1/f1+1/f2-separation/(f1f2), all in mm.
Symbols and units
- a
- First focal length (mm)
- b
- Second focal length (mm)
- c
- Lens separation (mm)
Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.
Assumptions & limits
Assumptions & limits
- Paraxial thin lenses in air; excludes afocal case. Supported limits: All required fields must be finite values of the exact declared type and within displayed bounds. Lists contain1–1000 finite numbers. JSON tables are numeric rectangular rows, at most100 rows and30 columns; individual tools have stricter shape/domain constraints. Paraxial thin lenses in air; excludes afocal case.
Are these inputs private?
These calculations run in your browser. A shared link contains the values you choose to share. Only questions submitted to the separate AI finder are sent to OpenAI.