Thanks Bruce! That's exactly the kind of info I was looking for. One of the main reasons I'm interested in a high magnification range is because I often combine still hunting with sitting on the side of a hill. For still hunting, I find that anything more than 4x makes it tricky to make a snap shot. The most important aspect of that lower magnification is the wider field of view. On the other hand, when I'm just sitting on the side of a mountain here in the Rockies, for long range shots, the higher the better...
Funny you would mention Zeiss since I just saw their advertisement this morning that specifically mentions their field of view. They say their field of view on the Z5 is "66% greater than a unit with 3x magnification." Not sure exactly what they're saying (seems like apples and oranges), but your post helped me make some sense of it.