The diameter of the aperture (in the sense above) which restricts the width of the light path through the whole system. For a telescope, this is the diameter of the objective lens. e.g. a telescope may have a 100 cm aperture
The size of the opening through which light passes in an optical instrument such as a camera or telescope A higher number represents a smaller opening while a lower number represents a larger opening
- A small, circular opening inside the lens that can change in diameter to control the amount of light reaching the camera's sensor as a picture is taken The aperture diameter is expressed in f-stops; the lower the number, the larger the aperture For instance, the aperture opening when set to f/2 8 is larger than at f/8 The aperture and shutter speed together control the total amount of light reaching the sensor A larger aperture passes more light through to the sensor Many cameras have an aperture priority mode that allows you to adjust the aperture to your own liking See also shutter speed
This is the diameter of the objective lens, or primary mirror usually expressed in millimetres, or sometimes in inches The larger the aperture, the greater the light gathering ability of the telescope
an iris in the lens which can cut off the outside portions of the lens, rendering them inactive Aperture values on the aperture ring represent the focal length of the lens divided by the diameter of the aperture
A hole The circular hole in the centre of a lens through which light passes to reach the film The size of the hole can be varied using the aperture control which in turn alters a diaphragm within the body of the lens Measured in f-stops Altering by one F-stop either halves or doubles the amount of light reaching the film
A small hole Usually with reference to a camera, the aperture is the hole in a camera that allows light to hit film The amount of light that gets through the aperture determines what a picutre will look like
The size of the primary optical surface of an astronomical instrument (telescope), usually given in inches, centimeters, or meters In the case of a reflecting telescope, the aperture usually refers to the size of the main mirror; in the case of a refracting telescope (of which binoculars are one example), the aperture refers to the size of the primary lens (which in binoculars is usually given in millimeters)
The opening in a lens that admits light Except in very simple cameras, the aperture can be varied in size by a diaphragm, which regulates the amount of light passing through the lens The relative aperture is measured as the focal length of the lens divided by the diameter of the aperture; this is expressed as an f-number: f/8, f/11, and so on
Lens opening The opening in a camera lens through which light passes to expose the film The size of aperture is either fixed or adjustable Aperture size is usually calibrated in f-numbers--the larger the number, the smaller the lens opening
The size of the lens opening through which light passes The relative aperture is measured as the focal length of the lens divided by the diameter of the aperture; this is expressed as an f-number: f/8, f/11, and so on
Aperture is the diameter of the light-gathering portion of a telescope In a Newtonian or Schmidt-Cassegrain telescope this is the size of the mirror In a refractor is is the objective lens that defines the aperture In small telescopes the aperture is often given in millimeters, while in larger scopes it is given in inches Usually the telescope is described by its aperture (for example, a person may refer to a "70-mm refractor" or a "6-inch Newtonian")
The 'opening' of a lens and a measure of its light gathering capability Relative aperture is the ratio between the focal length and effective aperture Measured in F numbers, generally speaking the lower the F the number the more light gathering power the lens has
The lens opening formed by the iris diaphragm inside the lens The size of the hole can be made larger or smaller by the autofocus system or a manual control
This is the lens opening A ‘metal leaf diaphragm’ covers the hole inside the lens and this controls the amount of light which will pass to expose the film The aperture is calibrated by an f number and effects the depth of field (ie the sharpness of the picture) The smaller the aperture (or f number) the sharper the object will appear
A physical opening that is part of the optical path in a device such as a scanner, photometer, or camera Most apertures are circular, but they may be rectangular or elliptical
A metal block containing a hole through which the radiation (photon or proton) beam passes Each portal for each patient requires a custom-made aperture The shape of the hole is the approximate shape of the target being treated by the beam Every patient has her or his own set of apertures; no other patients use them
The opening of the lens which controls the amount of light reaching the surface of the pickup device The size of the aperture is controlled by the iris adjustment
The diameter of the aperture (in the sense above) which restricts the width of the light path through the whole system. For a telescope, this is the diameter of the objective lens. e.g. a telescope may have a 100cm aperture