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Old May 15, 2005, 9:38 PM   #1
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Like will objects be twice as large as normal in a 200mm lens? Three times? And what about other lenths? 400mm? 600mm?

Is there an easy equation to figure this out?
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Old May 23, 2005, 9:59 PM   #2
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What ever the factor is, it will stay the same no matter what focal lenght you use. For a Dig rebel, 20D it is 1.6 so a 100 mm will become an effective 1.6*100 or 160mm. Same for a 200mm lens 200*1.6=320mm
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Old May 23, 2005, 10:50 PM   #3
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You cant think in terms of magnification. Think in terms of field of view. I can't find the equivalent field of view for each length of lens, but I'm sure someone else here can point you in the right direction.
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Old May 24, 2005, 5:37 AM   #4
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I could be wrong, but I think the question being asked has to do with consumer cameras having, say, 3x optical zoom, as an example. As far as I can tell, all of the consumer cameras take their longest focal length equivalent and divide by 35mm, so a camera with an equivalent of at least a 105mm lens is a 3x optical zoom camera.

For instance, my old Nikon CP5700 had a 9-72mm Zoom-Nikkor (equivalent to 35-280mm in 35mm photography). They divided 280mm by 35mm to get 8x optical zoom.

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Old May 24, 2005, 2:10 PM   #5
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In 35mm parlance a standard lens is around ~50mm, a normal person Field Of View (FOV). A 200mm is then 200/50 = 4x time the normal FOV while a 400mm is 400/50 = 8x the regular FOV.

If you get a 50-500mm zoom then the zoom ratio is 10x, and the FOV is 1x to 10x...

However if you get a 35-350mm zoom instead, the zoom ratio is still 10x, but the FOV is now 0.7x to 7x, i.e. it goes a little wider, but has less magnification at the long
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