Riflescope parts and terminology

Riflescope parts

1 - Objective Lens - Light gathering element of the scope.  Larger objective lenses have a better light gathering ability and produce better, brighter images.

2 - Objective Bell - Enlarged part of the scope tube which houses the objective lens.

3 - Scope Tube - Hawke scope tubes come in two sizes; 1 inch and 30mm.  In general, the 30mm scopes are stronger and designed to withstand heavier recoil energies.  The scope tube is the mounting area of the scope, where the scope mounts are to be fitted.

4 - Windage Turret - Used for adjusting the horizontal aim of the scope.  

5 - Elevation Turret - Used for adjusting the vertical aim of the scope.  

6 - Zoom / Magnification Ring - Used for adjusting the magnification setting of the scope.  

7 - Ocular Focus - Used for adjusting the focus on the reticle only.  Once set the ocular focus should not need to be changed unless the scope is being used by a friend, or if your eyesight has changed, e.g. started using corrective glasses.

8 - Ocular Lens - The viewing lens of the riflescope.  To get best viewing results place your eye at the correct eye relief listed on the scope's specification. 

9 - Eyebell Housing - The main housing of the ocular lens and reticle.

10 - Illuminated Reticle (IR) Battery Cap - The end battery cap can be unscrewed and completely removed so access to the battery is gained.  All Hawke Rifle Scopes use a single CR2032 battery.

11 - Illuminated Reticle (IR) Turret - Used to adjust the brightness level of the illuminated reticle.  Different styles of IR Turret exist:

12 - Side Focus (SF) - Used for adjusting the focus distance and parallax setting of the scope.  Some scopes have an extendable side focus wheel that can be fitted for extra grip and accuracy.

13 - Adjustable Objective (AO) - Similar to a side focus, the AO is used for adjusting the focus distance and parallax setting of the scope, but is less sophisticated that a side focus mechanism.

Terminology

Field Of View (F.O.V.) - The width of the scope's view.  This can be measured in terms of angle (degrees), or by a set distance. e.g. the F.O.V. of the FRONTIER 30 SF 2.5-15×50  is 14m wide when looking at an image 100m away on lowest magnification and 2.3m wide at an image 100m away when on highest magnification.  This is also equivalent to 42ft and 6.9ft respectively when looking at an image 100yds away.

Eye Relief - The correct distance for the pupil to be located from the eyepiece lens.  When at this distance the best viewing experience will be obtained.

Exit Pupil - The diameter of the viewing image when the eye is positioned at the correct eye relief.  This is calculated by dividing the objective lens diameter by the magnification. e.g. for an 50mm objective lens with the magnification set at 10x zoom, we divide the 50 by 10 to get 5mm.

Close Focus - The closest possible distance that the scope can be focused at.

Fully Multi-Coated (FMC) - Means that all lenses and glass surfaces have a coating layer. Multi-coated means that at least one of the major optical elements in the binocular has a coating.