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A Fresnel lens (/ ˈfreɪnɛl, - nəl / FRAY-nel, -nəl; / ˈfrɛnɛl, - əl / FREN-el, -əl; or / freɪˈnɛl / fray-NEL[ 1 ]) is a type of composite compact lens which reduces the amount of material required compared to a conventional lens by dividing the lens into a set of concentric annular sections.
PRISM is a code name for a program under which the United States National Security Agency (NSA) collects internet communications from various U.S. internet companies. [1][2][3] The program is also known by the SIGAD US-984XN. [4][5] PRISM collects stored internet communications based on demands made to internet companies such as Google LLC and ...
Augustin-Jean Fresnel[ Note 1 ] (10 May 1788 – 14 July 1827) was a French civil engineer and physicist whose research in optics led to the almost unanimous acceptance of the wave theory of light, excluding any remnant of Newton 's corpuscular theory, from the late 1830s [ 3 ] until the end of the 19th century.
A Fresnel rhomb is an optical prism that introduces a 90° phase difference between two perpendicular components of polarization, by means of two total internal reflections. If the incident beam is linearly polarized at 45° to the plane of incidence and reflection, the emerging beam is circularly polarized , and vice versa.
Fresnel proposed that the glass prism would carry some of the aether along with it so that "...the aether is in excess inside the prism". [5] He realised that the velocity of propagation of waves depends on the density of the medium and so proposed that the velocity of light in the prism would need to be adjusted by an amount of 'drag'.
The Fresnel equations give the ratio of the reflected wave's electric field to the incident wave's electric field, and the ratio of the transmitted wave's electric field to the incident wave's electric field, for each of two components of polarization. (The magnetic fields can also be related using similar coefficients.)
The New F-1 is an expandable system. It includes interchangeable viewfinders, focusing screens, motor drives, and alternate backs, all of which are specific to the New F-1. All other Canon components, such as the FD lens series, close up accessories (bellows, extension tubes, etc.), and Canon A and T Speedlights (except the 300TL) are also ...
Review bomb. A review bomb is an Internet phenomenon in which a large number of people or a few people with multiple accounts [1] post negative user reviews online in an attempt to harm the sales or popularity of a product, a service, or a business. [2] While a large number of negative reviews may simply be the result of a large number of ...