Find image distance from 1/f = 1/do + 1/di and magnification m = −di/do.
| Image distance (m) | – |
| Magnification | – |
Use this calculator for a thin lens (or a spherical mirror with the same algebra) in Cartesian sign convention: f > 0 for a converging lens, object distance do > 0 in front.
di > 0 is a real image on the far side; di < 0 is virtual. |m| > 1 is enlarged. If the object sits at the focal plane there is no finite image. Thick-lens and aberrations are ignored.
Focal length (m): Positive for converging. 10 cm is 0.1 m.
Object distance (m): Object to lens, in metres.
Image distance (m): di from 1/f = 1/do + 1/di.
Magnification: m = −di/do.
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