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Old Jul 20, 2008, 11:35 AM   #1
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I want to know is the optical zoom ofany digital cameras performs same as that of of Binoculars? Obviously the experience of viewing will be different but suppose if I compare the details in the still picture with what I'll be viewing through the binocular, will it be same? If not which one will give more details?

Suppose the lense size of Nikon Action 10X50 is 50mm which will gather light pretty good. In comparison what will be the number in Finepix s9600 where the optical zoom is 10.7X? Please throw some light on this matter so that I can also judge your decision without blindly following it.
I have seen camcorders of 48X optical zoom. so can a 48X optical zoom camcorder replace the role of 48X spotting scope? In this case also what will be the light gathering capability of the lense?From which specification can we tell that? Unfortunately I live in a place where its difficult to find someone who owns a good binocular let alone the idea of finding an astronomical or birdwatcher club
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Old Jul 20, 2008, 12:04 PM   #2
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Zoom factor 10x refers to the ratio between the shortest and longest focal lengths of the lens and has no other meaning. A lens that covered 28mm to 280mm would be a 10x zoom. But then so would a 50mm to 500mm lens which would yield much different coverage. Therefore a 48x camcorder lens would not have the same reach as a 48x spotting scope.

To relate a lens focal length to binocular power you would divide the focal length by the focal length of a normal lens. A normal lens would cover the normal view of the human eye. It is considered to be about 50mm for a 35mm film camera so a 500mm telephoto lens would be about 10 power in binocular terms.

The light gathering power of a lens is defined by the 'f' number. f/1 would be fantastic and only a couple of very expensive pro lenses ever had that specification. f/2.8 is common and by the time you get to f/5.6 the lens is next to useless in the dark.


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Old Jul 20, 2008, 12:08 PM   #3
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The Fijifilm S9100 (aka S9600) has a 28mm to 300mm lens in 35mm equivalent coverage. This would translate to 6 power at the 300mm end.

It is also f/2.8 - f/4.9 which would not be quite as good as the binoculars.

Have a look at http://www.tamron.com/lenses/learnin...comparison.php to see what various focal lengths cover.
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Old Jul 20, 2008, 12:23 PM   #4
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