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Prism is the fourth studio album by American singer Katy Perry.It was released by Capitol Records on October 18, 2013. While the album was initially planned to be "darker" than her previous material, Prism ultimately became a prominently dance-inspired record.
Galilean type Soviet-made miniature 2.5 × 17.5 monocular Diagram of a monocular using a Schmidt-Pechan prism: 1 – Objective lens 2 – Schmidt-Pechan prism 3 – Eyepiece. A monocular is a compact refracting telescope used to magnify images of distant objects, typically using an optical prism to ensure an erect image, instead of using relay lenses like most telescopic sights.
The unilateral cover test is performed by having the patient focus on an object then covering the fixating eye and observing the movement of the other eye. If the eye was exotropic, covering the fixating eye will cause an inwards movement; and if esotropic, covering the fixating eye will
Simulated animation of globe effect (right) compared with a simple pan (left) In photography, distortion is particularly associated with zoom lenses, particularly large-range zooms, but may also be found in prime lenses, and depends on focal distance – for example, the Canon EF 50mm f / 1.4 exhibits barrel distortion at extremely short focal distances.
••E Chart-do-; for those who can not read ••Landolt's broken ring chart-do-; for those who can not read ••Toys pr picture chart-do-; for children •Near vision-do-; to determine visual acuity of near vision ••Jager's chart-do- ••Printer's types of N series-do- ••Snellen's near chart (1/17th reduction of distant chart)
In the additive model, if the resulting spectrum, e.g. of superposing three colors, is flat, white color is perceived by the human eye upon direct incidence on the retina. This is in stark contrast to the subtractive model, where the perceived resulting spectrum is what reflecting surfaces, such as dyed surfaces, emit. A dye filters out all ...
An example of the Landolt C eye chart (also known as the Japanese eye chart.). Numerous types of eye charts exist and are used in various situations. For example, the Snellen chart is designed for use at 6 meters or 20 feet, and is thus appropriate for testing distance vision, while the ETDRS chart is designed for use at 4 meters. [16]
In photography, reciprocity refers to the relationship whereby the total light energy – proportional to the total exposure, the product of the light intensity and exposure time, controlled by aperture and shutter speed, respectively – determines the effect of the light on the film.