Editing Magnifying glass (section)

==Alternatives==
Magnifying glasses typically have low magnifying power: 2×–6×, with the lower-power types being much more common. At higher magnifications, the image quality of a simple magnifying glass becomes poor due to [[optical aberrations]], particularly [[spherical aberration]]. When more magnification or a better image is required, other types of hand magnifier are typically used. A [[Coddington magnifier]] provides higher magnification with improved image quality. Even better images can be obtained with a multiple-lens magnifier, such as a [[Hastings triplet]]. High power magnifiers are sometimes mounted in a cylindrical or conical holder with no handle, often designed to be worn on the head; this is called a [[loupe]].

Such magnifiers can reach up to about 30×, and at these magnifications the aperture of the magnifier becomes very small and it must be placed very close to both the object and the eye. For more convenient use or for magnification beyond about 30×, a [[microscope]] is necessary.

[[Image:Magnifying-fresnel-lens.jpg|thumb|right|A plastic [[Fresnel lens]] sold as a TV-screen magnifier]]
A ''sheet magnifier'' comprises many very narrow concentric ring-shaped lenses, such that the combination acts as a single lens but is much thinner.{{Citation needed|date=April 2025}} This arrangement is known as a [[Fresnel lens]]. Fresnel lenses are used as magnifiers, for example for reading printed text.