zoom lens


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zoom lens

a lens system that allows the focal length of a camera lens to be varied continuously without altering the sharpness of the image

Zoom Lens

 

a combination of a telescopic attachment and an objective lens, forming an optical system with a variable focal length. The mechanical motions of the individual elements of the telescopic attachment ensure that the image scale of an object varies smoothly within a specified range. The focal length of a zoom lens is varied, but the sharpness of focus of the objective and the relative aperture remain unchanged.

Zoom lenses are used most often on motion-picture cameras for creating the illusion that the camera is approaching or receding in cases where it is not desirable to move the camera relative to the object being filmed. Because the aberrations of the telescopic attachment and the objective lens are usually calculated separately, the same attachment may be used with different objective lenses.

L. A. RIVKIN

zoom lens

[′züm ¦lenz]
(optics)
A system of lenses in which two or more parts are moved with respect to each other to obtain a continuously variable focal length and hence magnification, while the image is kept in the same image plane. Also known as variable-focal-length lens; varifocal lens.
References in periodicals archive ?
The new HD zoom lens features a variable focal length from 20 to 200 mm, F/6 for a 2/3 inch camera.
The $1,000 titanium-body camera features include an equivalent 35-105mm zoom lens, plus a 4x digital zoom; and employ a SD memory card.
It records high-resolution images at 1280 x 1024, or at 640 x 480 resolutions, and the 3x aspherical zoom lens delivers 35mm equivalent of 35-114mm coverage.
Similar to other lenses Canon provides for its REALiS Pro A/V Series projectors, the RS-IL04UL Ultra Long Focus Zoom Lens includes independently floating elements, helping to ensure minimal image quality change and light loss throughout the zoom length of the lens, thus greatly reducing the need to over-specify projector brightness to compensate for light loss.
SANYO claims this new camera is the world's thinnest (23mm), smallest (124cc) and lightest (140g) among video cameras with a mega pixel or higher image sensor and with an optical zoom lens.
5:1 zoom lens with manual or motorized operation, high-resolution color CCD camera, manually operated x-y-z stages, and 1-micron linear scales.
4-times SMC PENTAX zoom lens offers outstanding wide-to-telephoto coverage to capture subjects with impressive clarity and sharpness.
6B is the Company's longest focal length range portable HD zoom lens offered (without an image stabilization system).
6B zoom lens is designed for use in diverse news and documentary situations, which can frequently involve rapid changes in subject distance and associated focal length," noted Larry Thorpe, senior fellow, Professional Engineering & Solutions Division, Canon U.
chromatic aberration, the XL wide-angle 3X zoom lens achieves 600 TV
2 kg, less than half the weight of the top-end zoom lens models that went on sale earlier this year.
This provides a large range of photographic opportunities as this continuos zoom lens can stop at any number of points to perfectly frame the picture.