MIKE GEORGE says: After scanning the advertisements myself, I can see what you mean. What do figures like 8×21 or 10×25 really mean?
Well, the first number is the magnification, so a specification which starts with an 8 magnifies the object eight times, when compared to normal vision. I find that, for practical work in the field, 8x magnification is about right. Go much beyond that, and you may have trouble holding the binoculars still enough – particularly on cold days when you might be shivering.
The second figure gives the diameter, in millimetres, of the object lenses – the big lenses at the front. The greater the figure the more is the light-gathering power, so big lenses give better performance as the light fades in the evenings.
However, for shooting, both weight and bulk have to be taken into account, so you might consider a pair of 8x25s. I still stick with a pair of quality 8x40s – I suddenly realise I have been using for the past 36 years! They are both bulky and heavy by modern standards, but still do the business!
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