Optics Terminology

ADJUSTABLE OBJECTIVE An Adjustable Objective is a feature on a scope that allows you to correct for any parallax. Some of our scopes have an adjustable ring around the objective lens housing (Ex. Shooter II Series), while others have a knob on the left side of the turret housing (Ex. Mark III Series). Reducing parallax with an adjustable objective equates to greater shot precision.
COATED OPTICS Lens coatings reduce the amount of light reflection, allowing more light to pass through the scope. The more light that a scope can take in, the brighter the targeted image will be, which is very important under low lighting conditions. Most NcSTAR scopes are Fully Multi Coated to maximize light transmission.
DURABLE CONSTRUCTION NcSTAR scopes are designed to withstand the toughest elements by using high quality aircraft grade aluminum with a hard anodized finish, providing a surface that is virtually rust and scratch proof.
EXIT PUPIL The exit pupil in an optics system is the circular beam of light being transmitted to your eye. To find the size of the exit for your scope or binoculars simply take the diameter of the objective lens and divide it by the magnification. For example, a 4x30 scope would have an exit pupil of 7.5mm (30 divided by 4 equals 7.5). The larger the exit pupil is, in relation to the entrance pupil of the eye, the brighter the image will be.
EYE RELIEF Eye relief is the distance needed between the shooter’s eye and the ocular lens (eyepiece) to achieve a full field of view and a comfortable aiming position. Some Scopes have longer eye relief than others, depending upon the application they are intended for. A pistol, for example, requires a scope with long or extended eye relief. When using a magnum rifle, allowing for a little extra eye relief aids in the safety of the shooter’s eye.
FIELD OF VIEW (FOV) Field of view for a scope or binoculars is the amount of area (in feet) visible from left to right, typically at 100 yards. At higher magnifications the field of view becomes more narrow. At low magnifications the field of view is wider. For quick target acquisition at close range (under 100 yards) a very wide field of view is desired, requiring a scope with low magnification.
MAGNIFICATION Scope magnification refers to the power size of the scope. For example on 4x30 scope the magnification would be a 4 power. In this case, the object that you are viewing will appear to be 4 times closer than with the naked eye. Lower powered scopes are most suitable for close range shooting, while high powered scopes are better for long range shooting.
OBJECTIVE LENS The objective lens is the front lens of the scope (lens closest to the target). The diameter of the objective lens is measured in millimeters. For example, on a 3-9x42 scope, the objective size is represented just after the “x”, in this case being 42 millimeters. Larger objectives, such as a 50mm objective, allow for more light to pass through the scope, equating to a brighter image. The larger the objective, the taller the mounting rings must be also.
OCULAR LENS The ocular lens (eye piece) is the lens that you look through to view your target. Most ocular lenses adjust in and out to sharpen the contrast of your reticle. Once set, you should not have to adjust your reticle again.
POWER RING Variable powered scopes (Ex. 3-9x42) have a power ring usually located directly in front of the ocular housing. By twisting the power ring you can control the magnification setting. So on a 3-9x42 scope you can zoom from 3 to 9 power and anywhere in between. On a fixed powered scope, such as a 6x42, there will not be a power ring because the magnification is permanently set at 6 power.
WINDAGE/ELEVATION TURRET The windage turret controls the left to right movement of the reticle, and is generally located on the right side of the scope. The elevation turret controls the up and down movement of the reticle, and is generally located on the top of the scope. NcSTAR offers a variety of scopes in 1/2, 1/4, and 1/8 MOA adjustments so you can choose the scope that’s right for you.
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