How to Choose an Optical Sight – 8 Things to Look
How to Choose an Optical Sight: Every hunter, having passed the five-year path from smooth-bore to rifled weapons, is faced with the task of choosing an optical sight. This article offers all the main points that you should pay attention to when choosing a scope.
Choosing an Optical Sight by Parameters
Table of Contents
Let’s briefly consider the main parameters that manufacturers indicate:
The lens is the most important element in sight, usually consisting of two or more lenses. The main task is to collect light reflected from objects. From this, it turns out that the larger the lens diameter, the more light will enter the scope, which means that the image will be brighter. In almost all cases, the name of the device indicates the optical diameter of the objective.
If hunting at the twilight time is supposed to be, the best telescopic sight will have a wide lens diameter. Diameters from 50 mm are considered high values. On the other hand, the larger the diameter, the longer and heavier the scope, which in some situations, will complicate aiming, for example, in running hunting.
The quality of the lens manufacturing determines how detailed the image will be. Several layers of anti-reflection coating are applied to the lenses to prevent light from entering the lens from being reflected back. Each manufacturer uses different types of anti-reflection coating.
The concept of parallax adjustment is emphasized separately. Beams passing through the lens are focused on the plane where the reticle is located. The misalignment of planes is called parallax and looks like an indistinct image of the object, and for detuning on the sights, you can find the lens focusing mechanism.
In scopes, focusing is located on the lens in the form of a ring or on the center’s side. The mechanism’s lateral arrangement allows for more accurate focusing, and, as a rule, such scopes are more expensive. The type of focus can be indicated in the names.
If the sight does not have any of the presented types, then it is set at a certain distance. Most often, these are sights designed for shooting at a distance of up to 100 meters.
Magnification is a ratio of how many times an object’s size differs when viewed with the naked eye and through an optical sight. Like the lens diameter, magnification is indicated in the names. The sights are divided into two options – constant and variable magnification.
Constant magnification sights are more convenient to use for specific distances, and they are easier to handle and more reliable in design due to the lack of moving elements. Variable scopes are suitable for different distances depending on the zoom range. How to select the correct multiplicity can be found in the corresponding article.
3. Removal of the exit pupil
An eyepiece, like a lens, consists of multiple lenses. The optimal image is obtained by placing the eye at the optimal distance from the eyepiece’s outermost lens. The characteristic of removing the exit pupil indicates the convenience and safety of using the scope.
When fired, the recoil causes the scope to move towards the eye, and the higher the value of the exit pupil removal, the safer for the eye. If the eye is located closer or further, then black “moons” appear during viewing relative to the set value.
Modern sights have an offset in the range of 70-90 mm, which belongs to the safety class. But don’t underestimate the impact of recoil when choosing a scope for a Magnum class weapon.
4. Output Lens Diameter
Exit pupil diameter is a characteristic directly related to the structure of the human eye. At different light levels, the human eye shrinks or enlarges the pupil diameter to control light output. With a lack of light, the pupil expands to 7 mm, with sufficient illumination, the diameter is 3-4 mm in the case of optical sight.
The optimal light transmission will be in the case when the diameter of the exit lens and the diameter of the pupil coincide, and thereby the entire luminous flux will fall into the eye.
The exit pupil diameter can be calculated independently by dividing the lens diameter value by the multiple. The formula for calculating the exit pupil diameter helps to choose the magnification of sights for use in the dark. For example, with a lens diameter of 50 mm, the optimal magnification should be 7-8 times.
5. Line of Sight
In the description of sights, there is a characteristic of the field of view of the optical sight. This value means what plane the sight sees at a certain magnification. The field of view is indicated in angular or linear units and depends on the lens parameters and magnification.
In the scope of variable magnification, the field of view will be higher at minimum magnifications. The example below shows the angular and linear values of the field of view of the Yukon Jaeger 3-9×40 sight:
6. Aiming reticle
Reticles are a separate topic in scope selection. Each manufacturer develops its own reticle options. The grids are divided into simplified hunting variations and tactical ones with a lot of marks.
The standard aiming reticle has horizontal and vertical guides, along which the shooter estimates the weapon’s blockage. For hunting, shooting is fundamentally fast, especially when the animal is moving.
Therefore, the aiming reticle of hunting scopes is a simplified view. There are grids with different line thicknesses or the presence in the center of a collimator mark in the form of a point or across, which is convenient to use when shooting at a moving target. When hunting long distances, bullet drop and crosswind corrected nets, such as Mil-Dot, are used. Examples of hunting nets:
The tactical reticle is used for accurate shooting at stationary targets. They are used to calculate the ballistic trajectory of a bullet, measure distances, and, as a rule, have a large number of corrective marks. Examples of tactical nets.
Grid backlighting is used to increase the visibility of lines or a central mark on a contrasting background or at dusk. Depending on the manufacturer, the backlight can be of different colors, but the common one is red.
For scopes of variable magnification, there is the concept of the reticle’s location in the first or second focal plane of the lens. For changing the magnification insight, the movable mechanism of the lens turning system is responsible.
If the reticle is located in the lens’s focus, which means in the first focal plane, then when the image is enlarged, the reticle also increases.
It turns out that the calculation of the distance is available for any multiplicity since the sect changes proportionally. When the reticle is positioned in the eyepiece’s focus, which means in the second focal plane, the reticle size does not change.
The first option is suitable for ballistic reticle and is used in expensive sights. Sights with a reticle arrangement in the second focal plane are cheaper to manufacture and are convenient for hunting tasks.
7. Mount types
Optical sights are cylindrical in shape. To mount the scope, the use of landing rings is common, with the exception of sights with an integrated bracket or landing tire. A bracket is individually selected for each gun, but the following parameters are always taken into account:
- Landing diameter of the sight. For fastening through rings, the diameter of the tube must be known. Common diameters are 25.4 and 30 mm, less often – 34 and 36 mm.
- The outer diameter of the objective. The bracket height is selected so that there is a gap between the lens and the barrel. When measuring the lens’s outer diameter, the protective cap, and focus wheel, if any on the scope, are taken into account.
- A safe distance from the eye. Depending on the seat’s location on the weapon, the sight is set at a distance from the eye, which is set by the exit pupil removal parameter.
8. Case features
When choosing an optical sight, pay attention to the features of the case. These include resistance to mechanical stress, protection against water ingress, the presence of inertial gases inside to prevent fogging during temperature extremes, a protective coating.
The drums for entering corrections, which can be open or closed, are considered separately. The closed type assumes the presence of protective covers to prevent accidental movement, which is mainly for using sights for hunting. The open type of drums implies frequent input of corrections, and latches are used to prevent shifting.
How to Choose an Optical Sight for Hunting
When hunting, there are no exact values of distances to the target, in contrast to trap shooting. Aiming is complicated by the possible movement of a hunter or an animal. The higher the speed, the lower the fold you need to use. At low magnification, the wide field of view allows faster aiming with a lead.
For example, a sight for driven hunting should have a small magnification range. The beast moves quickly over short distances, so a wide-angle of view is the main factor. Sights up to 4 times have this, and the 1-4x “pen” is considered popular. Since driven hunting, according to the rules, is carried out only in the daytime, the lens’s wide diameter can be neglected.
During the running hunt, it is assumed that the hunter will move when tracking the animal. As in driven hunting, the increased insight needs to be selected as little as possible due to the difficulty of shooting from hands.
But some animals do not let the hunter get close, so the multiplicity is selected with the expectation of using it at short and medium distances. For such cases, it is more convenient to use fixed sights with a low magnification value, for example 4x, or variable type with a range from 1x-2x to 6x-8x. Optical sights for running hunting differ from driven ones also by the increased diameter of the objective, since shooting can be carried out at twilight.
High multiplicity values are used in motionless hunts, for example, from an ambush. The hunter uses tripod and bipod supports to reduce vibrations. The selection of magnification depends on the distance, but it is common to use high values up to 12x, 16x. To maintain aperture ratio at high magnifications, the sights have impressive lenses up to 50-60 mm in diameter.
Sights with magnification over 16x are used exclusively for mountain hunting. Mountain hunting involves shooting at a great distance from the beast, which requires serious preparation. Scopes are often chosen with up to 24x range and ballistic reticle.
There are universal scopes for use in different types of hunting. Usually, these are scopes of variable magnification with a wide range. The minimum value is intended for shooting at short distances and is 2x-5x. The maximum value is intended for shooting at long distances and corresponds to 10x-20x.
The Best Riflescopes on the Market
Of course, riflescopes are divided into price classes, so we have selected in this section the best scopes for the hunter’s estimated budget.
Before choosing an optical sight, it is necessary to compare the estimated parameters and budget. For convenience, use the following list:
- First, it is necessary to compare the estimated firing distances and the target’s size, after which the multiplicity is selected.
- The lens diameter is selected based on the requirements of shooting at twilight time.
- Choose your reticle with a focus on target movement speed, ballistic performance, and personal preference.
- Decide if you need reticle illumination.
- If you have a large caliber, then check the sight’s eye relief, it should be higher than 70 mm.
- Depending on the shooting conditions, choose a sight according to the degree of protection against water ingress and the presence of gases inside the case.
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