How do I determine the appropriate zoom needed?

[nbstl68]

Other than viewing sample clips posted here and elsewhere of various cameras, how can I determine how far out a specific zoom range will be useful?
Is there a chart or grid or some formula for determining how far out a 4x zoom can see and clearly capture detail vs. say a 30x zoom?


For example, If I only want to see to the end of my driveway buying a 30x is surely too much camera but if I want to see small details 200 yards away maybe it is not enough?

 

[bguy]

You want a FoV calculator. You plug in the mm of the lens, and size of the ccd/cmos and the distance to the target, and it tells you the width of the frame. 10x isn't the number you're looking for, it just means the lens can zoom 10x the minimum lens size. That means if the minimum is 2.8mm, then it can zoom up to 28mm. So you need to calculate what size lens works for your situation.

Bradley

 

[nayr]

yep, the X is not what your looking for.. a 6-60mm and a 12-120mm lens are both 10x zoom, but one can see the same level of detail much much farther away than the other..

This site is a great help: http://ipvm.com/calculator
note how wide the frame is at the distance you input when you get so far out there sample images are worthless.