Riflescopes - Tech Talk

Coated Optics

Coatings on lens surfaces reduce light loss and glare due to reflection for a brighter, higher-contrast image with reduced eyestrain. Bushnell® riflescopes are coated with a microscopic film of magnesium fluoride. More coatings lead to better light transmission.

Exit Pupil

The size of the column of light that leaves the eyepiece of a scope. The larger the exit pupil, the brighter the image. To determine the size, divide the objective lens diameter by the power (a 4x32 model has an exit pupil of 8mm).

Eye Relief

The distance a scope can be held away from the eye and still present the full field-of-view. Bushnell riflescopes provide an extra margin of comfort and recoil safety with extended eye relief and soft neoprene eyepiece guards.

Field-of-View (F.O.V.)

The side-to-side measurement of the circular viewing field or subject area. It is defined by the width in feet or meters of the area visible at 100 yards or meters. A wide field-of-view makes it easier to spot game and track moving targets. Generally, the higher the magnification, the narrower the field-of-view.

Magnification (Power)

Riflescopes are often referred to by two numbers separated by an "x". For example: 4x32. The first number is the power or magnification of the scope. With a "4x", the object being viewed appears to be four times closer than when seen with the unaided eye.

Objective Lens Size

The second number in the formula (4x32) is the diameter of the objective or front lens in millimeters. The larger the objective lens, the more light that enters the scope, and the brighter the image.

Rugged Body Construction

Bushnell riflescopes use a high-durability aluminum alloy. They are also anodize-finished and are sealed to protect the inside from the elements. Each riflescope is rustproof, virtually scratch-proof and a beautiful complement to the most expensive firearm.

RainGuard® HD

Bushnell's permanent, patented, hydrophobic (water-repellant) lens coating prevents fogging by causing condensation from rain, sleet, snow or even your own breath to bead up into much smaller droplets than on standard coatings. Smaller droplets scatter less light which results in a clearer, brighter view. Now the hunter won't miss the shot of a lifetime because of rain or accidentally breathing on his eyepiece.

Ocular Lens

The lens closest to your eye.


A condition that occurs when the image of the target is not focused precisely on the reticle plane. Parallax is visible as an apparent movement between the reticle and the target when the shooter moves their head or, in extreme cases, as an out-of-focus image. Bushnell center fire riflescopes under 11x are factory-set parallax-free at 100 yards; rim fire and shotgun scopes at 50 yards. Scopes of 11x or more have an adjustable objective to adjust for parallax.


Resolution, or definition, is the ability of a scope to distinguish fine detail and retain clarity.

Precision Adjustments

The windage and elevation adjustments affect accuracy. Windage is the horizontal (left-to-right) adjustment, usually the side turret of the scope. Elevation is the vertical (up-and-down) adjustment, usually the top turret of the scope. Bushnell scopes feature 1/4 M.O.A. (1/4" at 1 windage 00 yards) or finerand elevation adjustments with audible clicks for greater precision.

FireFly™ Glowing Reticle Technology

Developed by Bushnell® engineers for the lowest-light hunting situations, the patented FireFly™ reticle illuminates the crosshairs after only a quick 10-second flashlight charge. Unlike battery-powered reticles, which often fail at the absolute worst times, the FireFly will glow green and you’ll see your crosshairs against your quarry. Featured on select Elite 3200 riflescopes.

Types of Coatings

Coated – A single layer on at least one lens surface.
Fully Coated – A single layer on all air-to-glass surfaces.
Multi-Coated – Multiple layers on at least one lens surface.
Fully Multi-Coated – Multiple layers on all air-to-glass surfaces.


Some binoculars are O-ring sealed and nitrogen-purged for total waterproof and fogproof protection. These modesl can withstand complete immersion in water and stay dry inside. The interior optical surfaces won't fog due to rapid temperature change or humidity.