Zoom lenses can capture distant objects with great clarity.
Zoom lenses on cameras enable distant objects to appear magnified in the resulting images. They are distinguished from normal lens by their extended focal length, which can be varied. They were developed from technology used in the manufacture of telescopes and have been in use since the early 19th century.
How Camera Lenses Work
Camera lenses are designed to direct light onto a sensor (either digital or film) in order to recreate an image accurately. The goal is to filter each ray of light as true to its original dimensions as possible. They are glass disks through which the light is refracted, creating an inverted image on the sensor. This is then developed the right way up in the darkroom or on a computer for digital cameras.
History Of The Zoom Lens
The first public report on the use of zoom lens technology for magnifying images was given during a meeting of the Royal Society in Great Britain in 1834. This was similar to the effects of telescopes and was not related to cameras, which were not invented until 1839 with the unveiling of the daguerreotype in France. The first patent for an adjustable camera lens was made in the United States in 1902, while the first zoom lens manufactured for modern 35mm cameras was launched in 1959.
Characteristics
What distinguishes a zoom lens is it comparatively long focal length. This is the distance between the lens and the sensor. It means that the field of vision is narrowed, resulting in light being concentrated onto the lens. This enables the photographer to capture clear images of subjects farther away from the camera. Zoom lenses are adjustable, enabling the angle of view to be changed. The name "zoom" refers to this ability.
Problems
Because of the relatively longer time it takes for the light from a distant subject to reach the camera, blurring for the minute involuntary shaking of the photographer's hands can affect images captured with a zoom lens. One method to counteract this is to use a short exposure time (the length of time that the shutter is open to allow light to enter and hit the lens). Also, because of the distance, perspective can be flattened in images taken with a zoom.
Applications
Zoom lenses are useful tools for any photographer. They are particularly beneficial when attempting to photograph subjects which the photographer does not want to know are being photographed. Thus, zoom lenses are often used in taking photographs of wildlife behaving naturally. They are also routinely employed by paparazzi photographers trying to get "candid" shots of celebrities.
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