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Saahmad
05-11-2011, 10:30 PM
Rifle scope Basics i found useful

1. Field of view

Riflescopes typically come in two different magnification set-ups:
1. Fixedpower
2. Variablepower
· Fixedpower scopes have a power magnification that is set and cannot be adjusted.Some common fixed powers include 4X, 6X, and 10X. Fixed power scopes are usedin both hunting and target shooting.
· Variablepowered rifle scopes feature a power magnification that can be adjusted towithin a set range, such as 3X9 or 4X12. While variable power scopes are themore popular style, fixed power scopes offer a more simply approach with lessmoving parts and adjustments during use.
· Thefield of view(commonly marked or called the FOV) is the actual area displayed as you lookthrough the scope. While some scope manufacturers measure it in degrees, mostnow measure it using feet. The larger the field of view means the more area youcan see. Field of view is particularly important in hunting as most huntersneed to track game through the scope before taking a shot.
· The magnification affects brightness, sothe higher the magnification power, the dimmer the view. The magnificationpower also affects the field of view. The higher the power, the smaller thefield of view. The lower the power, the wider the field of view. Whilemagnification is important, it needs to be balanced against other desirablecharacteristics when choosing your scope model.


2. Objective lens diameter
· Objectivelens diameter is the diameter of the objective or front lens measured inmillimeters (mm). This figure is generally shown at the second figure in ascope configuration. For example, a 4X32 scope has a magnification power of 4and a 32mm diameter objective lens. A 6X42 has a 42mm diameter objective lens.
·

· Thelines in the image above depict the objective lens diameter and how it'smeasured. Objective lens diameter is also considered a measure of the amount oflight that can enter a scope. Objective lens generally range anywhere from 32mmall the way up to 75mm. The larger the objective lens, the more light than canenter the scope.
· Noticethe amount of light in the 50mm compared to the 32mm? Please understand thatlarger objective lens will only transmit more light when they are set on theirhighest power. So if you took a 6X42 scope and a 8X50 scope made by the samemanufacturer, the 50mm model is only going to pull more light than the 42mmwhen the 50mm is set above six power.
· Keepin mind that the higher you go in objective lens diameter, the larger the lenswill be in size and heavier it will weigh. Also realize that some of objectivelens that exceed 48mm or so may require special rings and bases for mounting asthey will have to mounted higher off the rifle. This higher mounting can impacteye relief and result in a less than comfortable position during shooting. Formost applications, 38mm to 48mm will work just fine. I've got a scope with a50mm lens and it's only used for long range shooting.


3. Rifle scope reticle
A reticle is the pattern(which can vary) placed in the eyepiece of the scope which establishes thegun's position on the target. Reticles can be made from fine wire or etchedinto the glass itself. Reticles come in a wide variety of variations that rangefrom simple traditional style crosshairs all the way to illuminated mil dots(short for military dot). Here are some examples of different reticles:


These represent a smallsample of reticles that are currently available today. Some rifle scopemanufacturers produce their own specialized reticles. The reticle in the imageabove marked as "Firefly®" is a specialized illuminated modelproduced by Bushnell®.
In the grand scheme ofthings reticles probably won't play a huge role in your scope selectiondecision, but it can be important. Make sure you choose a reticle that worksyour specific type of shooting. For long range shooting or hunting (+400 yards)or long range competitive shooting, consider a reticle without a dot.
At longer ranges with smalltargets, the dot can actually cover up the target. A good friend of the authorhunts prarie dogs at long range and purchased a very expensive scope with amil-dot reticle. At long ranges, he found that the reticle dot was actuallylarger than the prairie dogs and covered them up

4. Scope lens coating
Allscope lenses are made from glass as it provides the clearest optical image.However, any time light strikes a glass surface, a certain amount on the lightis reflected away. The reflection reduces the amount of light passing throughthe lens, which impacts the brightness.
Lenscoating refers to the microscopic layer of chemical coating that is applied tothe air to glass surfaces on the scope. Coating the lens reduces the glare andreduces the loss of light due to reflection. Many scope manufacturers use amagnesium fluoride film for coating. A German based scope maker called Zeiss(which is still an elite scope brand today) was the first to start usingmagnesium fluoride coated lens in 1935.
Generally,more coatings leads to better light transmission and better contrast. Thecoatings are expensive and they greatly vary in type, number, and quality.
Hereare some explanations of common terms used to quantify coating:
· Coated:Has a single layer of coating on at least one lens surface.
· FullyCoated: Has a single layer on all air to glass surfaces.
· Multicoated:Has more than one layer of coating on at least one lens surface.
· FullyMulticoated: Has multiple layers of coating on all air to glass surfaces.
Here'sa idea of what coated lens versus uncoated lens would like compared:


Noticethe clearer and brighter difference on the coated side?
Whenscope shopping, take the time to read the fine print and determine how muchcoating the lens actually has. If you can afford it, go with fully multicoatedas this is the best choice in optical quality. As mentioned before, coating isexpensive and is generally reflected in the price. Fully multi-coated scopestend to be expensive. However, if you are ever hunting or shooting in low lightconditions like dawn or dusk, you will appreciate the benefits of multi-coating

5. Scope magnification or power

Scope magnification is amultiplication measurement compared to the average naked eye. Basically themagnification number determines how many times better you will see an objectthan with your naked eye. Magnification is typically the first number that yousee in scope performance.
For example, a 4X32 scopehas a four power magnification which means you can see 4 times better than youcould without the scope. A 6X42 scope has a six power magnification and an 8X32has an eight power magnification.
Here's a graphic image tohelp explain:
Scopesalso come in a variable or adjustable power that offers a range ofmagnification. With these scope models, there will be a range of numbers(usually going lower to higher) that are separated by a hyphen.Forexample, a 3-9X36 is very common hunting configuration. In an adjustablemagnification scope such as that, the magnification can be set anywhere fromthree power all the way up to nine power. Variable power scopes tend to be mostpopular for hunting applications.What'sthe best magnification power? It really depends on your needs

Courtesy : www.rifle-scope-guide.com (http://www.rifle-scope-guide.com)

wasifali89
06-11-2011, 09:27 PM
nice share

A R K TAREEN
09-11-2011, 03:03 AM
Nice and informative share brother, thanks for sharing.

taha
11-11-2011, 10:20 AM
Thanks for sharing! Can you tell also if scopes in discussion are specific to Air rifles only, or are also applicable to other rifles (firearms)? Sorry but I'm a noob...

Saahmad
13-11-2011, 12:06 AM
I guess, all rifles.