Thin Lens Image
Solve image distance and magnification using signed distances.
Your numbers
Signed image distance
Paraxial thin lens in air; positive image distance is real, negative is virtual. Aberrations and lens thickness excluded.
Scenario comparison
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Formula
Use 1/f = 1/dₒ+1/dᵢ and m = −dᵢ/dₒ. f is focal length, dₒ is object distance, and dᵢ is image distance in the same unit. A converging focal length and real object distance are positive; m is lateral magnification.
Solve image distance and magnification using signed distances.
Worked example
- Focal length (cm), converging positive
- 10
- Object distance (cm), real object positive
- 30
- Signed image distance
- 15 cm
- Lateral magnification
- -0.5
Scope and limitations
Paraxial thin lens in air; positive image distance is real, negative is virtual. Aberrations and lens thickness excluded.
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Formula version: 91cfdc85b63d · Example checked: