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About Rifle Scopes

Functioning of Rifle Scopes

Rifle scopes work by magnifying an image and by placing your eye on the same optic plane as your target. Since magnification works by bending light rays via a number of lenses within the scope, the higher the power of magnification, the longer the scope. 

The similarities that all rifle scopes share include a reticle or crosshair, a dot, a post or similar markings to help align the device with the target. A reticle or crosshair is a shape, usually a "+" shape, superimposed on an image (target) to aid with the alignment of the device. Some reticles use dots to mark the center of field-of-view or a post or similar markings to help view and center the image through the scope. Rifle scopes allow for precise shot placement and eliminate the problems associated with open sights. With open sights, the target must be aligned with two sights, while with a rifle scope the target must be aligned with only one reticle.

Rifle Scope Terminology

Adjustable Objective Lens (AO): Eliminates the parallax error by adjusting the objective lens. 
Elevation Adjustment: Shifts your aiming point along the vertical plane (higher/lower) by adjusting the top turret.
Eye Bell: Houses the eye piece and gets attached to the tube.
Eye Piece: Attaches to the eye-bell and holds the ocular lens.
Eye Relief: Refers to the distance between your eye and the ocular lens when you see the full field of view. 
Exit Pupil: The diameter of the light column leaving the eye piece, calculated by: [Objective Lens Diameter]/[Magnification].
Focal Plane (Image Plane): Term used to indicate the position of the reticle. First focal plane reticles - situated where the turrets are - increase in size with increased magnification. Second focal plane reticles - situated in the eye bell - remain constant in size with increased magnification.
Focus Ring: The ring on the eye bell, used to focus the reticle. This does not have anything to do with magnification.
Main Tube: the structure and mount for the eye piece, eye-bell and objective bell, as well as mounting rings/rail.
Objective Bell: Houses the objective lens and the main tube gets attached to it.
Objective lens: Collects the light that enters the scope. The larger the objective lens, the more light gets transmitted. Larget objectives are required for low light applications.
Ocular Lens: The lens nearest to your eye.
Parallax Adjustment: This adjustment places the image on the reticle plane and subsequently eliminates parallax errors when not looking exactly through the centre of the scope. 
Power (Magnification) Ring: Allows you to rotate and change the magnification on the scope.
Reticle: The crosshairs or "sight" of the scope.
Side Focus (SF): Side parallax adjustment knob, situated opposite the windage turret. 
Main Tube: the structure and mount for the eye piece, eye-bell and objective bell, as well as mounting rings/rail.
Windage Adjustment: Changes the aiming point of the scope on the horizontal plane (left/right).

Quality

The quality of your rifle scope can have a huge effect on whether or not your hunt is successful. Quality of the glass, lens anti-reflective coatings, structural and material quality, accurate and repeatable adjustment, etc. A large part of the price of a rifle scope goes into the quality of the glass and lens coatings. The quality of the rifle scope is at least as important as the quality of the rifle itself. 

Magnification 

Magnification is nothing more than what it says and should not be confused with quality. With a good quality scope, more detail can be seen on lower magnifications than on an inferior quality rifle scope at the same magnification. Choose a magnification range that is suited to your application. 1 or 1.5x Minimum magnification provides sufficient field of view when hunting dangerous game. 2-8x Magnification range is in most cases perfect for bush hunting. For general plains hunting of up to 250 m, at least a 3-12x or 4-12x magnification range is sufficient. For beyond 250 m ranges, higher maximum magnifications like 15x, 16x, 18x, 20x, 24x, 25x etc. can be selected, depending on the distances and the amount of target detail required. When horn lengths, thickness and colour need to be determined on long distances, maximum magnification is required. Keep in mind that on higher magnification the mirage distorts your point of impact more than on lower magnifications, the eye box becomes more sensitive and Image quality deteriorates. The higher magnification could therefore be used for selection, while the lower magnifications could be used for shooting. Also for tactical shooting and range shooting the magnification range is critically dependent on the specific application. 

Click here to download the complete Rifle Scope brochure

 

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