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post #6 of Old 06-23-2013 Thread Starter
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Re: Binocular Conundrum: Field of View?

I'm talking about ONE manufacturer, giving a 50% wider FOV for two different "same numbers" binocs they make. So however they define FOV, it is THE SAME definition, from the same maker, for both binocs.

Same thing. I'm not comparing apples to oranges, I'm saying that it doesn't matter which glasses you compare. 7x50 to 7x50, or 8x42 to 8x42, pick ANY SIZE you want and then compare two different bincos IN THAT SAME NOMINAL SIZE. Whether they are made by the same maker or two different makers, but the SAME NUMBERS on both glasses. As I said, I'm familiar with optics, I know pretty well that a 7x and a 10x will--or at least should--have very different FOVs under most conditions.

I'm still not understanding this. First off, I'll assume when you say the length between the front and rear lens you mean the length of the optical path, since that can be folded differently. But even so, if the magnification is the same, and the size of the image coming out the back is the same (as measured by the exit pupil), then the distance shouldn't matter. Same is same, if the apparent view is 10x "bare eye" sized, you can only blow things up so far UNLESS you change the size of the image. So in theory a wider FOV would require a wider exit pupil image. That exit pupil image "crops" whatever the apparent FOV is going to be, doesn't it?

Doesn't make sense, unless the exit pupil becomes a meaningless number.
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