Calculadora de Magnificação de Lente
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
M = img / obj
About this calculator
The Lens Magnification Calculator determines how much a lens magnifies or reduces the image of an object. Linear magnification (M) is calculated by dividing the image size by the object size, or equivalently, by the focal length divided by the difference between object distance and focal length. This tool is useful for photographers, biologists, and optics enthusiasts who need to predict the image size formed by a lens.
To use the calculator, enter the lens focal length and the distance from the object to the lens. The result shows magnification: values greater than 1 indicate enlargement, between 0 and 1 indicate reduction, and negative values indicate an inverted image. The formula assumes thin lenses and ideal conditions without aberrations.
When to use? In macro photography to calculate the magnification factor, in microscopy to estimate the magnification of an objective lens, or in optical projects to size lens systems. It is also useful for understanding the behavior of magnifying glasses and telescopes.
Cautions: The formula is valid only for thin lenses and real objects. In multi-lens systems, total magnification is the product of individual magnifications. Ensure consistent units (usually centimeters or millimeters). The object distance must be different from the focal length, otherwise the image forms at infinity.
Frequently asked questions
What does negative magnification mean?
Negative magnification indicates the image is inverted relative to the object, common in converging lenses when the object is beyond the focal point.
Can I use this calculator for thick lenses?
The formula assumes thin lenses. For thick lenses, results are approximate and may have significant errors.
What unit should I use for focal length and object distance?
Use any length unit, as long as both are in the same unit (e.g., centimeters or millimeters).
What happens if the object distance equals the focal length?
In this case, the image forms at infinity and magnification tends to infinity, which is not physically realizable.
Does this calculator work for diverging lenses?
Yes, but magnification will always be positive and less than 1 (virtual and reduced image). Use negative focal length for diverging lenses.