The lenses of a TEM allow for beam convergence, with the angle of convergence as a variable parameter, giving the TEM the ability to change magnification simply by modifying the amount of current that flows through the coil, quadrupole or hexapole lenses.

In addition to its photographic use, the afocal part of a zoom lens can be used as a telescope of variable magnification to make an adjustable beam expander.

For a given subject magnification, increasing the f-number ( decreasing the aperture diameter ) increases the DOF ; decreasing f-number decreases DOF.

Parameters listed on the prism cover plate describing 7 power magnification binoculars with a 50 mm Objective ( optics ) | Objective diameter and a 372-foot Field of view at 1000 yards

It is customary to categorize binoculars by the magnification × the objective diameter ; e. g. 7 × 50.

Second World War era night glasses usually had a lens diameter of 56 mm or more with magnification of seven or eight.

His skill in grinding lenses ( some as small as 1mm in diameter ) resulted in a magnification as high as 245x.

The telescopic sights used on sniper rifles differ from other optical sights in that they offer much greater magnification ( more than 4x and up to 40x ), and have a much larger objective lens ( 40 to 50 mm in diameter ) for a brighter image.

This will be much smaller than the object glass diameter, which gives the linear magnification ( actually a reduction ), the angular magnification can be determined from

In practice it is widely considered to be 2 × the aperture in millimetres or 50 × the aperture in inches, so a 60mm diameter telescope has a maximum usable magnification of 120 ×.

Telescopic sights are classified in terms of the optical magnification and the objective lens diameter, e. g. 10 × 50.

On fixed magnification sights the magnification power and objective diameter should be chosen on the basis of the intended use.

' In these cases, a 4 × 81 ( 4 × magnification ) sight would be presumed to have a brighter sight picture than a 2. 5 × 70 ( 2. 5 × magnification ), but the objective lens diameter would not bear any direct relation to picture brightness, as brightness is affected also by the magnification factor.

In the case of binoculars however, the two eyepieces are usually permanently attached, and the magnification and objective diameter ( in mm ) is typically written on the binoculars in the form, e. g., 7x50.

In that case, the exit pupil can be easily calculated as the diameter of the objective lens divided by the magnification.

The exit pupil width of say, a binocular, can be calculated as the objective diameter divided by the magnification, and gives the width of the exit cone of light in the same dimensions as the objective.

William Wimsatt and Cleanth Brooks, it seems to me, have a penetrating insight into the way in which this control is effected: `` For if we say poetry is to talk of beauty and love ( and yet not aim at exciting erotic emotion or even an emotion of Platonic esteem ) and if it is to talk of anger and murder ( and yet not aim at arousing anger and indignation ) -- then it may be that the poetic way of dealing with these emotions will not be any kind of intensification, compounding, or magnification, or any direct assault upon the affections at all.

The efficiency Af of an Af lens at the magnification Af is: Af.

In pinhole projection, the magnification of an object is inversely proportional to its distance to the camera along the optical axis so that a camera pointing directly at a flat surface reproduces that flat surface.

Whilst the magnification of both the field ion and atom probe microscopes is extremely high, the exact magnification is dependant upon conditions specific to the examined specimen, so unlike for conventional electron microscopes, there is often little direct control on magnification, and furthermore, obtained images may have strongly variable magnifications due to fluctuations in the shape of the electric field at the surface.

The combination of focal length, subject distance, and format size defines magnification at the film / sensor plane.

DOF is determined by subject magnification at the film / sensor plane and the selected lens aperture or f-number.

DMT crystal at 400x magnification.

Strand of human hair at 200x magnification

Image: FLY EYE. jpg | SEM image of a house fly compound eye surface at 450 × magnification.

Scale invariance is an exact form of self-similarity where at any magnification there is a smaller piece of the object that is similar to the whole.

A core dump gets its name from an old memory technology using tiny magnetic core s, shown here at 50x magnification.

Onions have particularly large cells that are readily observed at low magnification ; consequently, onion tissue is frequently used in science education for demonstrating microscope usage.

Transverse aberration occurs when different wavelengths are focused at different positions in the focal plane ( because the magnification and / or distortion of the lens also varies with wavelength ; indicated in graphs as ( change in ) focus length ).

In digital sensors, axial CA results in the red and blue planes being defocused ( assuming that the green plane is in focus ), which is relatively difficult to remedy in post-processing, while transverse CA results in the red, green, and blue planes being at different magnifications ( magnification changing along radii, as in geometric distortion ), and can be corrected by radially scaling the planes appropriately so they line up.

Photomicrograph made with a Scanning Electron Microscope ( SEM ): Fly ash particles at 2, 000x magnification.

This involves growing towards a ridge between the epidermal cells, followed by a perpendicular growth which end at the stoma. Rust hypha attacking stoma ( 1600x magnification ) Inside the stoma, the hyphae tips flatten out to form structures known as appresorium that lock to the cell walls.

Examples of natural fractals are coast lines and tree shapes, which repeat their shape regardless of what magnification you view at.

The focal length of a lens determines the magnification at which it images distant objects.

See the image above, at high magnification.

* VoiceOver — VoiceOver is an accessibility interface that offers the user magnification options, keyboard control and spoken English descriptions of what is happening on screen.

The magnification here is typically negative ; in photography, the factor is sometimes written as 1 + m, where m represents the absolute value of the magnification ; in either case, the correction factor is 1 or greater.

In this case, the magnification factor ( m ) must be taken into account:

* 28-300 / 4. 0-6. 3 ( 1. 6 ), 17 elements in 15 groups, 77 mm filter, 1. 9 m close focus, multicoated lenses, 570 g, f / 16 min, 1: 5. 5 magnification, Ø82 × 122 mm, sliding zoom

* SP AF 24-135 / 3. 5-5. 6 AD Aspherical Macro ( Model 190D ), 14 elements in 10 groups, 7 blades diaphragm, f / 22 min, 0. 4 m close focus, 1: 3. 3 magnification, 72 mm filter, 530 g, ø78. 5 × 80. 6 mm

* AF 28-200 / 3. 8-5. 6 Super Zoom XR Aspherical ( IF ) Macro ( Model A03 ) 15 elements in 14 groups, 7 blades diaphragm, f / 22 min, 0. 49 m close focus, 1: 4 magnification, 62 mm filter, 354 g, ø71 × 75. 2 mm ; replaced the 28-200 / 3, 8-5, 6 LD ( IF ) Aspherical Super ( 2. 7 )

* AF 28-300 mm F / 3. 5-6. 3 XR Di LD Aspherical ( IF ) Macro ( Model A061 ), 15 elements in 13 groups, 0. 49 m close focus, 1: 2. 9 magnification, 62 mm filter, ø73 × 83. 7 mm, 420 g, 9 blades diaphragm, f / 22 min ; replaced the 28-300 / 3, 5-6, 3 LD Aspherical ( IF ) ( 2. 6 )

In most cases, the image distance is not easily determined ; the depth of focus can also be given in terms of magnification m: