Hydralover suggested that somebody do an article on variety of scopes.
By no means I am a specialist.
But perhaps I can help with sorting things out.


[Image Converter/Focus Lens is my terms, TM says "elector lens" those terms are not familiar to me.
Also, Locking ring and Eye piece were switched. At least in my scope, the eye piece is the focus ring, and
an inch or two in front of that is the locking ring]


[What the Numbers Mean]

You see numbers such as 3-9x40 or 2x20.

3-9x means magnification. You see objects 3 to 9 times as big as you can see with naked eyes. Which means magnification is adjustable. 2x20 means just 2 times the magnification, no adjustment in magnfication.

40 means the diameter of the object lens in mm; lens that's facing the target and gathering the light for you. The bigger the diameter, the more light it allows in. Bigger object lens makes the image brighter and clearer. 2x20 means 2 times magnification, and object lens being 20mm in diamenter.



[Field of View]

Naked eyes can see about 150 degrees. But if you look through your scope, naturally, you are seeing only one spot out of that 150 degrees of human field of view. Field of view simply means, how wide your view is at certain distance. Usually, it is measured at 100 yards of distance. Depends on manufacturer, 3-9 times magnification would give you about 35 feet to 15 feet (at 100 yards). Lowest magnification would give you wider field of view, 35 feet wide. Hightest magnification would give you narrowest field of view, 15 feet.


[Exit Pupil]

When the image is shown on the ocular lens (or eye piece; the lens closest to your eye), image is not always as big as the eye piece. When magnification goes up, the image on the eye piece gets smaller. This is usually measured in mm. Smallest image (biggest magnification), is about 6mm. Largest image (smallest maginifcaiton) is about three times that, 18mm. It makes sense because magnification is 3-9. 9 being 3 times of 3.

Bigger magnification, such as 14 times magnification, makes the exit pupil as small as 3mm, making it hard to see.

[Eye Relief]

Eye relief is the required distance between your eye and the ocular lens. Rifle scope is not a microscope, and you don't stick your eye to the eye piece. One needs certain distance between the lens and his eye, and that is eye relief.

[Scope Rings]

Scope rings are what's attaching your scope to your rifle's rail. Most common scope body tube diameter is 1 inch(25mm), but there are 3/4 inch tubes, and 30mm tubes, even 40mm tubes. Depends on the diameter of the body tube, you have to choose the right rings. Bigger lens often accompaies bigger body tube, but not always.

[Scope Rail]

For our Mil-sim purposes, we can find picatinny rain most often. These are found everywhere, and scope rings also fit picatinny rails most often.


[Magnification]

Magnification is nothing special. As it gets higher, there is a trade off. So getting the highest magnification isn't always a good thing. Higher magnification will make the image darker. Also, to allow higher magnification, there is moving parts and more lenses. These are not always good. Highest maginifcation tends to be a bit blurrier as the moving parts are at their limit. Also higher magnificaiton will give you smaller image(exit pupil) on the ocular lens. Also field of view is narrower. There is only one way to compensate little bit for these faults; bigger object lens. But bigger object lens is always more expensive, heavier, and bulkier. Know these trade-offs well, and choose a scope that fits your need.

[Adjusting Magnificaiton]

Adjusting manfication is easy enough, just rotate the magnification ring, and adjust eye piece to focus.
But know that highest magnification could bring chromatic abbration (color separation), and blurred image. Higher quality scopes would have less of this effect. But most scopes, even cheap ones, provide sharp image when you use one less maganifcation than the top magnificaiton offered. Mine is 3-9x, but I usually use it at around 8x, because the image is sharper at 8. If you are moving to a postion, it would be better to start your magnificaiton at 3x. If you have to fire quickly, highest magnificaiton could fail you because of narrow field of vision. Once you are in the posion, you can adjust magnificaion to higher end.


[Fixed magnification]

Fixed magnification is usually set at lower magnification. Such as 2 times or 4 times. This allows easy and fast target aquisition. And no need to adjust, and the scope is small and light. 2 times magnification would give you wide and bright field of view, and thus make it easy to find your target. AUG has 1.5 maginifcation scope for that reason. Only slightly better than naked eyes, and wide view. I feel even 4 times magnification is sufficient for airsoft snipers. But I must admit, when I do shoot at my paper target at 100 feet, I can hardly pin point where my BBs land with just 4 times magnificaiton.


[Reticles]

Reciles are crosshairs. Most of them have increments cut into the crosshairs, and you can use them to measure the distance of your target. However, since airsoft BBs don't go beyond 200 yards, for airsoft purposes, it hardly matters. Simple cross hair with increments are useful enough.

[Windage & Elevation]

Most scopes allow you to adjust windage (sideway adjustmen) and elevation (up and down adjustment). Military snipers and hunters would adjust windage and elevation in the field. For airsoft purposes, you cannot sit on your belly 150 feet away from your target, and click away with your windage and elevation adjustment. But you can pre-adjust your scope to have your rifle zeroed at certain distance, and in the field, you have to adjust windage and elevation by pointing slightly into the wind, and aim high if the target is beyond zeroed point.


[What you Need]

Think about what you need. Sometimes I want magnification greater than 9x. But, for high magnification such as 12x to be effective, the object lens must be big, otherwise, exit pupil is too small, and the image is too dark to be useful. Rule of thumb would be to go over 9x, object lens must be 50mm or bigger. Object lens as big as 50mm cost $200-$300. There are cheaper Chinese brand scopes that have 50mm lens, but they probably do not use top of the line lens, making them darker than top of the line scopes, which means even under a tree canopy, your target might be too dark to see with high magnification. Name brands like Leupold, Carl Zeiss and Nikon produce world class lenses that are brighter, and their 50mm scopes start from $400 to $2,000. Considering that deers don't shoot back, but airsofters do, fancy scope is not something you want to expose to flying BBs.

For the snipers, 3-9x 40 is most common, and very inexpensive. You may wish you want greater magnification, but for greater magnificaiton to be done right, you need to spend enourmous amount of money. 3-9x40 is practically all you need for airsoft sniping.

There are also fancy reticles that lights up. That's a personal taste. But because of light apperatus, sometimes the scope body tube is 40mm in diameter, bigger than usual.

This post has been edited by Von Luck: Jun 26 2007, 11:12 PM

very useful!

A bit of a tip: You do not have to look to airsoft websites to find a decent scope for your AEG/Rifle/etc. Scopes built for BB guns, usually found at WalMart/equivalent or sporting goods stores offer scopes for pretty much the same price. Only problem, the mounting rings are rarely geared for picatinny rails, allthough this can be remedied by a pair of rings from some site like airsoftgi

well... thats clears up a few things.

Let's hope the bb doesn't travel through the scope and hit you in the eye

thx dude helped so much

Well, I would have to say that that is a very nice review that covers basically everything. It was very well written and you did your research or had already known and decided to post it. This should be a lot of help to the beginners that want to know how scopes work and the basic concept of everything. Thanks for the post!

haha like in Saving Private Ryan

very nice post

Tnks dude very helpfull!