field of view


Also found in: Dictionary, Thesaurus, Medical, Legal, Acronyms, Wikipedia.

field of view

(field) The area made visible by the optical system of an instrument such as a telescope at a particular setting. It is expressed in the form of its angular diameter. The field of view of a telescope usually increases with decreasing magnification, and depends on the eyepiece in use. A wide field may be obtained with specially designed eyepieces or with telescopes such as the Schmidt. If the telescope optics produce a flat field, the image will be focused at the center as well as at the edge of the field of view.

Field of View

 

The field of view of an optical system is the part of space or of a plane imaged by the system. The size of the field is determined by the system’s components—such as stops or the mounts of lenses, prisms, and mirrors—that restrict the beam of light rays. A distinction is made between angular and linear fields of view. The former is measured in angular units and is used in dealing with systems designed for observing very distant—essentially infinitely remote—objects; telescopes, field glasses, and many types of cameras are examples of such systems. The linear field of view is measured in millimeters or centimeters and is used with systems, such as microscopes, in which the distance to the object is small.

Figure 1

In Figure 1, A is the center of the system’s entrance pupil. The angular field of view is the angle 2ω at which the entrance port S1SS2 and the corresponding part of the object plane O1O2 can be seen from A. The linear field of view is the linear dimension O1O2. OO is the system’s axis of symmetry. In the general case, the planes O1O2 and S1S2 are not coincident, and vignetting with a ring width of BB1 occurs. If, however, the plane S1S2 is made coincident with the object plane, the boundary of the field of view is sharp. Efforts are made to achieve this effect in many optic tubes and other optical instruments by placing a field stop in the focal plane of the objective.

The angular field of view in the object space is inversely proportional to the angular magnification of the system. In binoculars the field ranges from 5° to 10°, and in the largest telescopes it does not exceed a few minutes of arc. In special wide-angle photographic lenses it can reach 120° to 140° or even 180°. The vast majority of microscopes are fitted with a set of replaceable eyepieces whose magnifications and, consequently, linear fields of view 2l in the object space are different. Eyepieces with 2l = 18 mm are often used. In many eyepieces, however, the field is greater or smaller than this value. In polarizing microscopes and stereomicroscopes, eyepieces with a field of up to 25 mm (wide-angle eyepieces) are often used. The linear field of view of a microscope as a whole is equal to 2l/β, where β is the linear magnification of the microscope objective.

field of view

[′fēld əv ′vyü]
(optics)
The area or solid angle which can be viewed through an optical instrument. Also known as field.

field of view

field of viewclick for a larger image
Field of view in a head-up display.
i. The angle between two rays passing through the perspective center of a camera lens to two opposite sides of the format.
ii. The total solid angle available when looking through a sight or a head-up display.
iii. The look angle of a seeker. See look angle.
References in periodicals archive ?
Difficulty for the driver to recognize the point of view (perspective), sightline, and field of view shown in the monitor
Field of view denotes the width of the focused image as it appears through the eyepiece.
We put the Navy in an environment where they own a three-to-five panel configuration and they could grow up to nine for 360-degree field of view," he said.
Yet there remain substantial shortcomings to night vision systems, including low resolution digital displays and constrained field of view.
The camera series offer a low unit price and a remarkably wide field of view.
This is a very sparse collection of stars that hangs together best under dark skies in the wide field of view offered by 7x or 10x binos.
Field of view is 345' at 1,000 yards for the 8x56, and 330' at 1,000 yards for the 10x56.
A larger field of view to help avoid situations where the tips of the instruments collide.
Waterproof and fogproof, it offers center focus and a wide field of view (Steiner, 1-800-257-7742, www.
An addition to the company's on-line 360[degrees] profile measurement solution family has a field of view that is 150 mmx 150 mm and compliments earlier released models having fields of view of 25, 50, 75 and 100 mm.
horizontal field of view, which is much larger than the previous field of view (71 mm at 0.
The Interchangeable Component Eyeshield (Ice) from Eye Safety Systems (ESS) is an innovative lightweight eye protection system that offers a combination of high-ballistic impact resistance, unrestricted field of view and a selection of 2.