Optics
Magnification
Positive magnification is upright, negative magnification is inverted.
The Formula
m = -di / do
Positive magnification is upright, negative magnification is inverted.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| m | Magnification | unitless | The ratio of image height to object height. |
| di | Image distance | centimetres | The distance from the lens to the image. |
| do | Object distance | centimetres | The distance from the lens to the object. |
What Each Symbol Means
munitless
Magnification
The ratio of image height to object height.
dicentimetres
Image distance
The distance from the lens to the image.
docentimetres
Object distance
The distance from the lens to the object.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate a thin lens equation page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate A Thin Lens Equation, filed under Science. Every number the guide produces comes from substituting into this one line.