What Is the Difference Between Resolution & Magnification?

Magnifying lenses enhance an image's size, not its resolution.

Resolution and magnification are two concepts in the field of optics. Magnification is the enlargement of an image, while resolution is the ability of an optical device to provide detail of an image.

Magnification

Magnification is achieved by bending light in order to change the size of an object's image. Telescopes, magnifying glasses and microscopes are instruments that magnify images. These devices can only magnify up until a certain point after which further magnification will not be distinguishable to the naked eye; further magnification is called empty magnification.

Resolution

Many optical instruments refer to a level of resolution, with higher levels being better. A common misconception is that resolution is measured in megapixels; this is only an order of magnitude measurement. Camera images also have pixels that are unusable or indistinguishable from one another. Any two points in an image closer to each other than the radius of the Airy disk (the circular pattern of light focused on a point) are indistinguishable from each other.

Misconceptions

Many believe that a lens that can produce a 4 megapixel image is twice as powerful as a 2 megapixel lens. However, megapixels are products; this means that doubling the length and width of the image actually quadruples the image's area.

References

• The Luminous Landscape: Understanding Digital Camera Resolution
• Digital Camera Buying Guide: Digital Camera Resolution
• Georgia State University: Simple Magnifier