What does this Specification Mean ?

Discussion in 'Nikon' started by Brahmaasmi, Aug 22, 2008.

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  1. Brahmaasmi

    Brahmaasmi Member

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    I have a Nikon P80 ..I know that it's Lens is ranging from 28 - 486 mm (Wide angelled to Telescopic)

    There is a Specification in the Bottom of my camera ..

    4.7-84.2 mm 1:2.8-4.5

    What does that mean

    I undersatnd F stop value is mentioned as 2.8 to 4.5 ,but not clear !

    Can someone explain me ? what does that ratio meant for?
     
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  2. Brahmaasmi

    Brahmaasmi Member

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    Can refer this link , where the specification is mentioned .... Any reply is welcome!

    http://nikonusa.com/Find-Your-Nikon/Product/Digital-Camera/26114/COOLPIX-P80.html
     
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  3. usapatriot

    usapatriot Well-Known Member

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    4.7-84.2mm refers to the zoom range of the lens. The P80 has an 18x zoom lens.

    2.8-4.5 refers to the aperture of the lens as it changes when the lens is zoomed in or out. It's at f/2.8 zoomed out all the way and at f/4.5 when zoomed in all the way.
     
  4. David Rasnake

    David Rasnake News/Review Writer News/Review Writer

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    Your camera has an equivalent or effective range of 28-486mm, but the actual focal length of the lens is 4.7-84.2mm. Why the difference? It has to do primarily with the size of the sensor: because you camera has a smaller sensor than a frame of 35mm film, the lens's actual focal length has to be shorter to perform like a 28-486mm lens would on a 35mm camera.

    We use 35mm-equivalent standards (i.e. 28-486mm) rather than absolute focal lengths for convenience, as a way of "speaking a common language" in a sense. But this isn't the actual focal length of the physical lens on your camera; that's 4.7-84.2mm.

    As USAPatriot said, the other spec is aperture.

    dr
     
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