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A reflex finder is a viewfinder system with a mirror placed behind a lens. The light passing through the lens is reflected by the mirror to a focusing screen, usually ground glass. The image formed on this ground glass can be observed directly, giving a waist-level reflex finder, or through a redressing optical device (set of mirrors or prism ...
The Maddox rod test can be used to subjectively detect and measure a latent, manifest, horizontal or vertical strabismus for near and distance. The test is based on the principle of diplopic projection. [1] Dissociation of the deviation is brought about by presenting a red line image to one eye and a white light to the other, while prisms are ...
The Canon FT QL is a 35mm single-lens reflex camera introduced by Canon Inc. in March 1966. It has a Canon FL lens mount compatible with the large range of FL series lenses. The FT can also operate the later Canon FD series lenses in stop-down mode, but the earlier R series has a different lens aperture mechanism and cannot be used, although ...
Canon made two fast lenses, the FL 50mm 1:1.4 and the FL 58mm 1:1.2, in order to compensate for the light loss. As the shutter curtain is permanently exposed to light without being protected by a moving mirror, a metal, rather than fabric curtain is used, which prevents the possibility of burning by being accidentally pointed at the sun, with ...
Wood (1905), [1] Bond (1922), [2] and Hill (1924) [3] Construction. Var. elements in Var. groups. A fisheye lens is an ultra wide-angle lens that produces strong visual distortion intended to create a wide panoramic or hemispherical image. [4] [5] : 145 Fisheye lenses achieve extremely wide angles of view, well beyond any rectilinear lens.
Amici prism. An Amici prism, named for the astronomer Giovanni Battista Amici, is a type of compound dispersive prism used in spectrometers. The Amici prism consists of two triangular prisms in contact, with the first typically being made from a medium-dispersion crown glass, and the second from a higher-dispersion flint glass.
Levelling or leveling ( American English; see spelling differences) is a branch of surveying, the object of which is to establish or verify or measure the height of specified points relative to a datum. It is widely used in geodesy and cartography to measure vertical position with respect to a vertical datum, and in construction to measure ...
The Canon EOS M200 is a digital mirrorless interchangeable-lens camera first announced by Canon Inc. on September 25, 2019. [1] Canon EOS M200 incorporates the proprietary image processor that allows the camera to capture still images up to 6.1 fps using the fixed focus and 4 fps burst mode. The EOS M200 can be connected to all EF, EF-S and TS ...