Laser rangefinder 

Ranges are not being guessed but measured

 

Laser rangefinders are very modern hunting accessories even though they have only been used in hunting circles for about two decades. Before, this equipment was only used for military purposes and was not accessible to the general public. The purpose of laser rangefinder while hunting is only one and that is to accurately determine the animal/target range so we can get the most appropriate chance of an accurate hit. With knowing the distance, the shooter can accurately take into account the bullet drop.

Modern laser rangefinders usually also show us the inclination and equivalent horizontal range which is very important when hunting in the mountains. Hunters who have knowledge, experiences and suitable equipment for long-range shots absolutely need the laser rangefinder. Shots fired at long range targets without this equipment are more or less blind shots rather than well-thought and deliberated. Target ranging by a feeling is usually followed by big mistakes which can quickly be foreseen by using the rangefinder. In one of our previous articles it was described how difficult is to shoot on great distances, however, this article will present more detailed laser rangefinders and its features. This will be helpful when choosing the right laser rangefinder.

 

Principle of usage

A principle of usage for laser rangefinders is quite easy to explain; rangefinder first sends a laser beam and then senses the reflection of this beam from the objects on a suitable sensor. With a sufficiently precise measurement of the time between the laser beam delivery and the reception of its reflection it is easy to calculate the distance to the object where the laser beam is reflected. Of course, the usage of modern laser distance meters is a bit more complicated since different manufacturers have worked out the basic principle of usage with development and have achieved greater accuracy and reliability of it. It is worth mentioning the difference between laser rangefinders for civilian use and those meant for military use. These civilian devices have a built-in laser labeled “class 1“, which means that its power does not exceed the limit that would be harmful to the eyes. The maximum range of civilian lasers is about 3,000 meters and is not harmful to human or animal health. Most laser rangefinders display distances in meters or yards.

 

Actual range of measurement

 The laser beam in ideal conditions could travel unchanged very far but its diameter widens with the distance in the atmosphere and also its strength decreases due to collisions with impurities in the air. Because of this, all laser rangefinders have a limited range of measurement. The range of measurements depends on many different parameters- the power of the laser beam, the sensitivity of the sensor, the laser beam frequency, and many other technological parameters. In general, more expensive and technologically advanced rangefinders have a larger range of measurement than the cheaper ones. The latter, anyway, use false sales approaches since many cheaper rangefinders often have much higher numbers in its tags than their actual range of measurement is. It should also be noted that in order to achieve the maximum range of measurement it is necessary to measure the distance to objects with a large reflecting surface such as houses, large rocks, and similar. In the case of measuring the distance to smaller objects such as game, the effective range of each device is decreased. The smaller the surface fewer laser beams are being reflected.

 

Methods of measurement: the first object, in the rain, continuous

Most laser rangefinders can be adjusted to enable different ways of measuring the distance to the observed objects. The latter is especially important in certain situations because the wrong distance could be measured which can then lead to the unnecessary wounding of the game. In the basic mode, laser rangefinders measure the distance to the observed object from which most laser beams are reflected. Of course there are cases where we want to measure the distance to the animal or the target that stands in the meadow before the forest. At that time more laser beams will be reflected from a large background than a small object in the foreground and the laser meter will display an incorrect measurement if no proper measurement method is selected.  Basically, all laser meters have English as the primary language of menus and settings. The method which allows measuring the distance to the first object and not the largest object is called “first target priority“. First target priority is used when hunting and for golf. A very frequent case which also requires a change in the measurement method is when the laser rangefinder is used in the rain. The most modern and expensive laser rangefinders already allow automatic adjustment of the way of measuring the distances in the rain while cheaper ones still need to manually adjust the mode of operation when it is raining. There are also some other ways to operate the laser rangefinders which can usually be set up but they are not essential for hunting purposes. It is necessary to mention the method of continuous measurement that gives the distance without interruption even if we do not focus on only one object but the rangefinder is moving during the measurement. This mode of operation is called „scan mode“.

 

Measuring the inclination

Hunting laser rangefinders are primarily intended to determine the distance to the game before firing at distances where it is necessary to consider significant bullet drop. In the mountains when knowing the actual distance the information about the inclination of the measurement line is also needed. More on how to consider the inclination in long range shooting is described in one of the previous articles, “Optics for Long Range Shooting“. The advanced laser rangefinders also offer measurements of inclination and they also give the incline in angular degrees at a distance. With additional software (ballistic program) such measurements also give an equivalent horizontal distance ( EHR- equivalent horizontal range) to the target or game. With EHR, the shooter takes into account only the horizontal component of the distance to the target/game.

 

Types of laser rangefinders

Figure 1

Laser rangefinders for hunting use are always fundamentally added to the optical device. Unlike other laser rangefinders used in forestry, construction, and elsewhere, when hunting, it is essential that the rangefinder gives the distance to the object (game, target, etc.) that the shooter sees through the optical device.Hunting rangefinders have an internal display for showing the measured distance (in the field of vision) and not on the outside of the case. Figure 1 shows both options of the internal display of the measured distance, namely the transparent view and display of the distance in the dark frame at the bottom of the field of view. Hunting rangefinders are most often added to the monocular, binoculars or riflescopes.

Monoculars with a laser rangefinder

Figure 2

The first monocular with the added laser rangefinder was produced by Leica in 2000 and since then, this is the most common and popular form of laser rangefinder ever since. Practically, all laser rangefinders of this type have a separate optical part and a laser measuring part, which can be seen in Figure 2. The latter does not affect the optical quality of the compound intended for observation, as is possible with some other forms of hunting laser rangefinders. In most of these devices, the optical part has a 6x magnification and a lens of objective diameter between 20 and 32 mm. The more advanced monoculars with the laser rangefinder enable the inclination measurements, a ballistic program and the ability to measure the distance of objects up to 2500 meters. The main advantages of this type of rangefinders are a small size and the affordable price.

 

Binoculars with laser rangefinder

Figure 3

The first laser rangefinder was a part of Leica Geovid 7×42 in 1992 binoculars. Nevertheless, these devices were not as rapidly expanded in the market as monoculars with a laser rangefinder. The main reason was their size, weight and much higher price. Due to the desire for the smallest possible dimensions, many of these devices have a laser system incorporated inside the optical part. Through this same lenses, visible light passes through, allowing observation and laser beams that allow measuring the distance. In such binoculars, elements of the laser measuring system are added to the construction of lenses and prisms. Although this design contributes to a smaller size, it’s frequent that the optical properties of the binoculars are very seriously affected. Most often, the image in such binoculars has a slightly yellowish or bluish tone, and the light transmittance is significantly worse. Most binoculars with an added laser rangefinder, have a darker image and the use of them in the dusk is below average. Nevertheless, such binoculars are also a significant advantage for the hunter, since there is no need to carry two pieces of equipment (binoculars and monocular with a rangefinder) while hunting. It is also the easiest and quickest way to measure the distance between game observation. The binoculars with a laser rangefinder are shown in Figure 3.

 

 

Figure 1: The left side shows how the measured distance in the center of the field of vision is displayed, which is most often found in monoculars and binoculars with a built-in laser rangefinder. On the right side, it is shown how the display of the distance is usually shown for riflescopes with a built-in laser rangefinder, in the lower part of the field of view.

Figure 2: Monoculars with an added laser rangefinder typically have a laser measuring set installed under the optical compound, through which the user observes distant objects during measurement.

Figure 3: Binoculars with the added laser rangefinder have a button or more buttons for measuring the distance and setting the operating mode on the center “bridge”.

 

Riflescopes with a laser rangefinder

The riflescopes with the added laser rangefinder followed very soon after the first such observation binoculars were presented. The first riflescope of this type was presented by Swarovski, the LRS 3-12×50 model in 1997. Later, the development of such riflescopes was mainly in two directions. Many manufacturers have decided to produce low-cost riflescopes that have a laser measuring system added to the optical construction. This approach, however, allows a smaller mass, smaller dimensions and also a lower price, but due to electronic laser equipment within the optical construction, they offer poorer optical properties and poorer light transmittance. The prestigious European manufacturers produce riflescopes that have a laser measuring device separated from the optical system. Such riflescopes have the same good optical properties as the ordinary ones, and at the same time offer all the advantages of knowing the shooting distance. In general, long range shots are by far the easiest with this sort of laser rangefinders, as the shooting distance can be determined in the field of view. Figure 4 shows two such scopes, namely, scopes with an external laser compound and scopes with a laser measuring system built inside the optical lens construction. Most riflescopes, however, allow you to measure the distance, but you still need to manually set the reticle on the turrets. The exception is the Burris Eliminator model, which moves the aiming point by changing the illumination of the reticle.

 

Conclusion and recommendations

Figure 4

The laser rangefinder is today an indispensable tool for all hunters who often decide for long range shooting. A long-distance shoot cannot be precise and ethical if we do not know the distance to the game we want to harvest. Of course, just like in all other areas, here is the eternal question of how to choose the most suitable laser rangefinder. Certainly, binoculars and, in particular, riflescopes with a built-in laser rangefinder are the best choice for the simple use. Nevertheless, there are quite a few limitations that need to be mentioned. Currently, only the most expensive binoculars, binoculars made in Europe, and riflescopes of this type offer decent optical properties. For most US, Japanese and Chinese products of this type, it is still better to select separate components and have a laser rangefinder in form of monocular separately, as well as classic binoculars and classic riflescopes. Monoculars with an added laser rangefinder have the same (even the cheapest) optical and laser compound separated, and therefore it is usually less problematic with a low light picture and unnatural colors. Because of their small size, it is very easy to put them into a small pocket and they can be a very useful tool on the hunt.

 

 

Figure 4: On the left side there is a riflescope with an external laser measuring device attached to the side of the case, and on the right side there is a riflescope that has a laser aiming part added inside the optical structure. In such riflescopes, laser beams and visible light travel through the same lenses.

Leave a Reply

Your email address will not be published. Required fields are marked *