magnifying

Magnifying is the act of making an object appear larger or more detailed than it does at normal viewing distance. In optics, magnification describes how the image size or the apparent angular size of an object is increased by a lens or a system of lenses. Linear magnification compares image height to object height, while angular magnification compares the angle the image subtends at the eye to the angle of the object itself.

A simple magnifier is a convex lens, commonly a handheld glass. By placing the lens between the eye and the object, light rays are refracted to form a larger image. The strength of a magnifier is often expressed in diopters, D = 1/f, with f the focal length in meters. Shorter focal lengths yield greater magnification. In practice, magnification is described for different viewing setups: when the image is placed at the near point (about 25 cm) or when the eye can relax for distant viewing.

More powerful systems use multiple lenses. A compound microscope uses objective and eyepiece lenses to multiply magnifications, while a telescope increases the apparent angular size of distant objects. Loupes and reading glasses are common magnifiers for close work. Digital magnification enlarges images using a camera sensor or software, but it may reduce optical detail and introduce blur or interpolation artifacts.

Applications of magnifying devices include reading small print, inspecting electronics or jewelry, studying biological samples, and precision crafts. Magnifying is a fundamental tool in science, education, medicine, and industry, valued for revealing detail that is not visible to unaided eyes.