Magnification Power - This can often be a subject of debate among birdwatchers.
Most hand-held binoculars are in the 7 to 12 power magnification range. 7 and 8 power are considered a general-use range because they usually have a larger field of view, which is the maximum angle a particular model of binocular can see. This is usually expressed as a number of feet in width that can be seen at a standard distance from the binocular (usually 1000 yards). A good range for field of view is 350 to 400 feet. Higher magnification binoculars (9 to 12) have relatively lower field of views - lower 300 feet range. But, if you're mainly using them for birdwatching, this is not often a big problem. So, if you want to use binoculars for a wide range of uses (nature viewing, sports events, scenery, etc.), a lower magnification is fine. If you mainly want to use them for birdwatching, a higher magnification binocular will enable you to see more detail. Besides field of view, another tradeoff of using higher magnification binoculars is that the image will often shake a bit more, especially if you have unsteady hands.

Company Resource:     Big Porro Binoculars, Compact Porro Binoculars
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