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Maddox wing. The Maddox Wing is an instrument utilized by ophthalmologists, orthoptists and optometrists in the measurement of strabismus (misalignment of the eyes; commonly referred to as a squint or lazy eye by the lay person). It is a quantitative and subjective method of measuring the size of a strabismic deviation by dissociation of the ...
The strength of the prism is increased until the streak of the light passes through the centre of the prism, as the strength of the prism indicates the amount of deviation present. The Maddox rod is a handheld instrument composed of red parallel plano convex cylinder lens , which refracts light rays so that a point source of light is seen as a ...
The lens has an EF mount and works with EOS film and digital cameras. The lens comes in two different versions: Canon EF 70–210mm f/4 AFD (1987–1990) Canon EF 70–210mm f/3.5–4.5 USM (introduced 1990) The variable-aperture USM model utilizes a rotating ring instead of a push-pull system for adjusting zoom. The lens was superseded by the ...
Macro photograph of a common yellow dung fly ( Scathophaga stercoraria) made using a lens at its maximum 1:1 reproduction ratio, and an 18×24mm image sensor, the on-screen display of the photograph results in a greater than life-size image. Headshot of a dragonfly taken with a 100 mm macro lens coupled with a 50 mm lens in reverse at the end.
Prism dioptres. Prism correction is commonly specified in prism dioptres, a unit of angular measurement that is loosely related to the dioptre. Prism dioptres are represented by the Greek symbol delta (Δ) in superscript. A prism of power 1 Δ would produce 1 unit of displacement for an object held 100 units from the prism. [2]
The EF 24–105mm f/4L IS USM is an EF mount wide -to- telephoto zoom lens. It was introduced by Canon in 2005 to complement the well-regarded 17–40mm f/4L USM and 70–200mm f/4L USM . The EF 24–105mm f/4L IS USM lens is often compared to the other L series zoom of comparable range, the 24–70mm f/2.8L USM, losing one full stop but ...
Canon EF 35–80mm lens. The EF 35-80mm f/4-5.6 USM lens is a family of EF mount wide -to- normal zoom lenses manufactured and sold by Canon. There were five versions made. One contained a piezoelectric motor, three contained a micro motor, and one contained a USM motor.
The Canon EF 35-70mm f/3.5-4.5 is an EF mount wide -to- normal zoom lens. It is one of the first lenses in the Canon EF series. It has the same zoom system and 9 lenses in 8 groups layout as the Canon New FD 35-70mm f/3.5-4.5 [1] although it is unclear whether the actual optical design is identical. In October 1988, Canon announced the EF 35 ...
The EF 100–300mm refers to three telephoto zoom lenses produced by Canon. They are of the EF lens mount that is compatible with the EOS line of cameras. The three versions are: f/ 5.6. f/ 5.6L. f/ 4.5–5.6 USM. The two 5.6 versions were contemporaries, launched at the beginning of the Canon EOS system. The L version had a different optical ...
Canon EF 35–105mm lens. The EF 35-105mm lens is a family of EF mount wide -to- normal zoom lenses manufactured and sold by Canon. There were three versions made. The first version was released in 1987 as an f/3.5 - f/4.5 aperture lens. [1] The next was released in 1991 as a f/4.5 - f/5.6 aperture lens. [2]