Thin Lens Equation Calculator

Find image distance from object distance and focal length.

Object distance

Focal length

Image distance 15

Magnification (x) -0.5

Formula: 1/f = 1/dₒ + 1/dᵢ

Step-by-step with your numbers:

1. Values used:

2. Object distance = 30

3. Focal length = 10

5. Image distance = 15

6. Magnification = -0.5x

Did we solve your problem today?

The thin lens equation relates object, image and focal distances.

The math behind it

1/f = 1/object distance + 1/image distance. Magnification = −image ÷ object.

object 30, f 10 → image 15, magnification −0.5.

Negative image distance?

Means a virtual image on the same side as the object.