Longman Dictionary of Contemporary English
Wiktionary
n. (context photography English) A lens containing a mechanical assembly of inner lenses, allowing the focal length to be changed rapidly.
WordNet
n. a camera lens that magnifies the image [syn: telephoto lens]
Wikipedia
A zoom lens is a mechanical assembly of lens elements for which the focal length (and thus angle of view) can be varied, as opposed to a fixed focal length (FFL) lens (see prime lens).
A true zoom lens, also called a parfocal lens, is one that maintains focus when its focal length changes. A lens that loses focus during zooming is more properly called a varifocal lens. Despite being marketed as zoom lenses, virtually all consumer lenses with variable focal lengths use varifocal design.
The convenience of variable focal length comes at the cost of complexity - and some compromises on image quality, weight, dimensions, aperture, autofocus performance, and cost. For example, all zoom lenses suffer from at least slight, if not considerable, loss of image resolution at their maximum aperture, especially at the extremes of their focal length range. This effect is evident in the corners of the image, when displayed in a large format or high resolution. The greater the range of focal length a zoom lens offers, the more exaggerated these compromises must become.
Zoom Lens is an independent Los Angeles-based record label founded and operated by May Yim since 2009. The label was created "in order to explore the implications of popular culture on the human condition and the duality of musical creations discovered across the digital landscape."
Usage examples of "zoom lens".
With the sun behind his back, it was safe to use the camera's zoom lens.
Before returning the camera to its Ziploc bag and putting it in the drybag, he twisted the zoom lens down to its 50mm focal length and, lying on his back, got the Maltese Cross on the focusing screen.
He adjusted the zoom lens and the focus, and the face of the hanged boy, much enlarged, came sharply into view.
From a hook on the bulkhead Chase took a still camera with an 85-mm-200-mm zoom lens and hung it around his neck.
The second one is a tracking camera with a telephoto zoom lens, that, up to half a mile, can give the clarity of resolution that one would expect at the distance of ten feet.
Even with the longest focus of the zoom lens, they looked small and distant.
With the big zoom lens, thanks to the perfect clarity of this airless world, he could almost get close-ups even from here, when the action started.
A small black aperture with a tubular object jutting from it, on which Morin now swung the lights and shifted to a zoom lens for a close-up view.