binoclulars

[robodad]

When looking for binos, it is important to keep in mind that your comfort is first and formost or you won't use them as much so keep in mind that the larger the exit pupil is the better you will be able to see through them, take any set of binos and look backwards through them holding them at arms length, that small hole you see is the exit pupil and the larger that is the better you will see through them.

A 5mm exit pupil will be about the max you will need as over time our eyes (pupil) will only ever expand that far so getting the highest exit pupil will be more comfortable  then a high magnification and you will be able to see better in lower light.

Here is how you calculate it, Take the small number ( and divide it into the larger objective number (42) and you get 5.25mm, with a 10x42 you will get a 4.2mm exit pupil so some of the light gathering capabilities is significantly reduced !!
 

[ZRS-8x42]

Bigger is not necessarily better.  Usually I find if I can't tell what I need with 8x, 10x won't work either.  I've had both out together a lot trying to figure out what I liked best.  I settled on 8x.  Why?  The fov is better, the eyestrain is less, the image is typically sharper and brighter with an 8x.  Heat mirage at distance in open country is magnified by higher magnification as well.  Whatever imperfections there exist in the binocular are also magnified more with 10x as opposed to 8x.  8x binoculars are a lot easier to hold steady too.

But the image of the 10x is 20% bigger than the 8x.  So, what you get from your question is answers from users who like 8x and users who like 10x. That comes down in almost all cases to strictly personal preference.  I can tell you what I like.  Somebody else can tell you what they like.  When it gets right down to it, you sort of have to figure that for yourself.

When you spend less money for a binocular, get the 8x.  It is easier to make better less powerful glass than more powerful glass at lower price levels. If you are looking at a roof prism binocular, it is a lot more important to be sure you are buying one with phase coating first.  Worry about magnification later.

In addition to the FOV discussed by Steve and exit pupil mentioned by robodad, higher magnification binoculars of the same model series also has a shorter eye relief. It may not be an issue for most people, even the ones with glasses. But someone may find the eye relief is too short to see the whole FOV.  The drive home message is that when designing optics, everything is about optimization and compromise of different competing factors: higher power--> narrower FOV, wider FOV--> lower power, etc, etc. When choosing binoculars, your decision is also made after evaluating the pros and cons of each model and figuring our which parameter is the most important to you for your application.  I normally recommended customers to start with 8x first if they asked my own experience, unless they knew exactly 10x was what they wanted.  As Steve said, you would not see an object with 10x either if you could not see it with 8x. Although 8x is my personal favorite (I think now I am hooked to 7x), 10x should not have any issue with image stability. Some people can push it to 12x. But again, the eye-relief with 12x can become a real issue for people wearing glasses.

[h2ofowlr]

If you plan on scoping a hill side for a while.  I would look at a good pair.  Pay the money, it will help eliminate the head aches.  I picked up the Leupold 10x42 pinnacles.  They are nice.