Lens Magnification Calculator

What Is Lens Magnification?

Lens magnification describes how large an image appears compared to the object. For thin lenses, linear magnification is the ratio of image distance to object distance with a sign convention that indicates orientation.

Magnification Formula

$$m = -\frac{d_i}{d_o}$$

$m$ is magnification, $d_i$ is image distance, and $d_o$ is object distance. A negative value means the image is inverted; $|m| > 1$ means enlarged, and $|m| < 1$ means reduced.

Thin Lens Equation

$$\frac{1}{f} = \frac{1}{d_o} + \frac{1}{d_i}$$

Example: for $f = 10\,\text{cm}$ and $d_o = 30\,\text{cm}$, image distance is $d_i = 15\,\text{cm}$ and magnification is $m = -0.5$ (inverted and half size).

Frequently Asked Questions

What does negative magnification mean?

A negative magnification means the image is inverted relative to the object. The absolute value still tells you how much larger or smaller the image is.

When is the image virtual?

For lenses, a negative image distance $d_i$ indicates a virtual image on the same side as the object.

Can magnification be greater than 1?

Yes. $|m| > 1$ means the image is larger than the object. Microscopes and magnifying glasses produce enlarged images.

What happens when the object is at the focal point?

When $d_o = f$, rays emerge parallel and the image forms at infinity. The thin lens equation has no finite solution for $d_i$.

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Lens Magnification Calculator

What Is Lens Magnification?

Magnification Formula

Thin Lens Equation

Frequently Asked Questions

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