Thin Lens Equation
Table of Contents
For light passing near the optical axis of a thin lens, the lens equation relates the focal length of the lens, the object distance, and the image distance. The equation is given by:
$$ \frac{1}{f} = \frac{1}{d_o} + \frac{1}{d_i} $$
Where
- (\small f) is the focal length of the lens,
- (\small d_o) is the object distance, and
- (\small d_i) is the image distance.
All distances are measured from the lens, and the distances and focal length can be positive or negative. A positive focal length indicates a converging lens, while a negative focal length indicates a diverging lens. If the image distance is positive, the image is real and on the opposite side of the lens from the object. If the image distance is negative, the image is virtual and on the same side of the lens as the object.