fov和焦距的关系

When comparing the edge definition of different binoculars, it is vital to not only use the same types (e.g. 10 x 42) only, but also take the fields of view into consideration. If one pair has a field of view of 120 m and another 100m at 1,000 m only, it is easier for the second to have better edge definition. However, this “benefit” comes with a considerable loss of field of view.

Field of viewvs angleof view

The love of nature is the main reason for going hunting. We share this passion and hope to inspire you with exciting stories and interesting facts.

The field of view cannot be calculated from the pure type designation (e.g. 10 x 42) but are specified by the optical design. The size of the prism and the eyepiece in particular determine which image angles can pass through the binoculars. The lens diameter does not affect this it only influences the brightness.

This paper presented a bicubic uniform B-spline wavefront fitting technology to figure out the analytical expression for object wavefront used in Computer-Generated Holograms (CGHs). In many cases, to decrease the difficulty of optical processing, off-axis CGHs rather than complex aspherical surface elements are used in modern advanced military optical systems. In order to design and fabricate off-axis CGH, we have to fit out the analytical expression for object wavefront. Zernike Polynomial is competent for fitting wavefront of centrosymmetric optical systems, but not for axisymmetrical optical systems. Although adopting high-degree polynomials fitting method would achieve higher fitting precision in all fitting nodes, the greatest shortcoming of this method is that any departure from the fitting nodes would result in great fitting error, which is so-called pulsation phenomenon. Furthermore, high-degree polynomials fitting method would increase the calculation time in coding computer-generated hologram and solving basic equation. Basing on the basis function of cubic uniform B-spline and the character mesh of bicubic uniform B-spline wavefront, bicubic uniform B-spline wavefront are described as the product of a series of matrices. Employing standard MATLAB routines, four kinds of different analytical expressions for object wavefront are fitted out by bicubic uniform B-spline as well as high-degree polynomials. Calculation results indicate that, compared with high-degree polynomials, bicubic uniform B-spline is a more competitive method to fit out the analytical expression for object wavefront used in off-axis CGH, for its higher fitting precision and C2 continuity.

field ofview中文

The field of view depends on the magnification, i.e. in general lower magnification levels have a larger field of view than higher levels. Therefore, when comparing different binoculars you must compare those with the same magnification only.

Unlike binoculars or spotting scopes, riflescopes generally have a smaller field of view and it is given at 100 m instead of 1,000 m. For safety reasons (recoil), however, a complete view can be obtained from a much larger distance (eye relief).

Depthof field

field ofview乐队

Very small fields of view give the impression of looking through a tunnel. There is a lot of black on the outside and a small image area in the middle. this undesired effect occurs on simple products and primarily on many zoom binoculars.

The field of view describes the area seen when looking through the optics – without moving them. For example, if you look at the edge of a forest through binoculars at a distance of 1,000 m and see an area covering 120 m, the binoculars have a field of view of 120 m/1,000 m.

fov是什么

Occasionally, the viewing angle or objective viewing angle is given, e.g. 6°. The field of view and viewing angle can be easily calculated:

Wide angle binoculars, on the other hand, shine with very large fields of view that offer a wide overview and comfortable observation. The field of view is so large that the image circle in the eyepiece appears at an angle of 60° or higher. This angle at which the image is observed in the eyepiece, is the subjective or eye-side viewing angle. The 60° threshold that determines the predicate “wide-angle” is specified in an ISO standard. Is a field of view, e.g. 120 m at 1,000 m, good or bad for binoculars? The answer depends on the magnification. 10x binoculars with this field of view would be very good (subjective viewing angle approx. 69°), a 7x pair with this field of view would be rather weak (subjective viewing angle of 48° only). The subjective viewing angle shows immediately if the field of view is pleasantly large and comfortable or if a tunnel vision can be expected.

The ADS is operated by the Smithsonian Astrophysical Observatory under NASA Cooperative Agreement NNX16AC86A