Free Lens Equation Calculator

Calculate image distance using the thin lens equation: 1/f = 1/do + 1/di.

cm
cm

Image Distance

15.00 cm

Magnification-0.5000

Image Distance vs Focal Length

Thin Lens Equation

The thin lens equation relates object distance, image distance, and focal length.

Formula

1/f = 1/d_o + 1/d_i

Positive focal length for converging lenses, negative for diverging. Magnification: M = -d_i / d_o. Negative M means inverted image.

Example Calculation

An object 30 cm from a converging lens with focal length 10 cm.

  1. 011/f = 1/do + 1/di
  2. 021/10 = 1/30 + 1/di
  3. 031/di = 1/10 - 1/30 = 3/30 - 1/30 = 2/30
  4. 04di = 15 cm
  5. 05M = -15/30 = -0.5 (inverted, half size)

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