How Does a Laser Rangefinder Work

How Does a Laser Rangefinder Work

How Does a Laser Rangefinder Work

You might have come across some articles that have discussed quite well about what a rangefinder is. To prevent dealing with unimportant talks, this writing piece will just directly detail the perfect answers to what the questioning headline states; how does a laser rangefinder work? Therefore, laser rangefinders have optoelectronic systems through which they convey electromagnetic pulses that are packaged in beams of light known as laser. Meanwhile, laser beams are often reflected off from the surface of targets, and then returned to the device. Following that, the electromagnetic systems of the device process the received beam to measure the distance involved. This measurement is done by the analysis of the beam’s travel time basically in 2 planes with regards to the delay in phases of the emitted as well as reflected light waves of the electromagnetic systems, which is a common method in laser rangefinders of the phase-type. 

Another form of distance measurement that involves a laser beam is the direct measurement of the pulse’s travel time from the device to its target and conversely. Also, this is common in the laser rangefinders of the pulse type. To discuss further, other rangefinders carry out highly accurate as well as the fastest measurement of distances. These types are known as interferometric rangefinders, but they are very expensive likewise they are easily damaged. Therefore, they get to be unreliable while using them for hunting or other forms of applications. 

Range and Range error

Normally, the light beam is narrow but it gets to spread when it travels over a long distance because of the divergence that laser beam undergoes, together with scintillation and wander effects of the beam. Furthermore, this is caused by air bubbles present in the air lying above the earth’s surface (i.e. an atmospheric distortion) along the path of the beam, which acts as lenses that range from microscopic to bigger sizes. Range error often occurs from combined effects of the atmospheric distortions and laser beam’s divergence as well as the lateral displacement of the heat bubbles of the atmosphere by transverse winds, bringing about difficulty with obtaining an accurate object distance measurement. For an object located behind bushes or under a tree, some part of the light beam might become reflected off the branches or leaves of the tree/bushes once they are positioned before the object, therefore the light returns early and a low reading is produced.


Time of flight principles are applied to the laser rangefinder

A rangefinder can help in distance calculations, take for instance when you push the button on the device, this makes an infrared laser to shoot toward what you target and it rebounds to the device instantly. The device then gives an acute measurement of the microseconds that were taken for the rebound, it then directly gives the calculations of the object distance from you. 

You, therefore, need no worries as this device can easily calculate whatever shots you give.


When it comes to determining the precision or better say; the accuracy of the rangefinder is based on consideration of the laser pulse rise or fall time. Rangefinders using very sharp laser pulses and detectors with a very fast speed can perform the ranging of an object over a distance of few millimeters.


After getting to know just little about the mode of operation of this device, yet advancement in technology also brought about the rising question; how does a laser rangefinder work? 

Time of flight: the rangefinder measures the exact time taken for a light pulse to travel to its targeted location and back to its source. Since the speed of light is being known, and the exact measurement of time has been taken, the distance can then be calculated distinctly. However, lots of pulses are being fired orderly providing a commonly used average response. 

The multiple frequency phase-shifts: perform the measurement of phase-shifts of several frequencies on reflection and then find a solution to some simultaneous equations for it to give a final measurement.

Interferometry: this is the most accurate and the most useful skill for measuring changes in distance rather than total distances calculated.


The laser rangefinder can be used in several sectors as well as for different purposes. They include: 

Deer Hunting


When out in the field, the use of laser rangefinder can help you with making very accurate shots with your rifle. Reason being that you can easily zero in quite well when landing shots on your target since you would have already measured a precise distance from it to you. There are some other units of this device that can particularly measure the angle of elevation, with which you can make more accurate shots. Besides, this happens to be great when you are bow-hunting.  

It’s better off to go for tough/rugged rangefinders when going for hunting because you may have to battle with some weather variations like when rainy or foggy. It should be able to also work in low light conditions because all your hunting expeditions won’t be limited to sunny days. Note that, a rangefinder particularly gets most required when trying to take shots over a long distance.


In the area of sport, lots of golf tournaments permit using laser rangefinders for the measurement of distances from a target to a player. The knowledge of a target’s distance helps you to make the right choices of what club to use and how best to play when next you want to make a swing. As this device has several components and features, some of its units can do an automatic focusing on your target flag for the easier game experience. 

For the permission of any player to employ this device during play, all other extra features like recommendations for club selection, slope measurements, etc. must be switched off in your unit.


In the field of forestry, several works incorporate measurement in their execution which could be in form of distance measurement or measuring what a tree’s height could be, and this can be done easily using the rangefinder. You may need to know that rangefinders employed in forestry are designed in a more rugged form compared to most other rangefinders, which is because, considering the possibility of field conditions to be wet as well as rough, such device will be needed. Rangefinders specifically made for forestry works have features like anti-leaf filters with which it can perform better. There are cases where this device is designed in a way that its working system includes reflectors for more accuracy in terms of measurement.  


In the field of construction, most industries make use of rangefinders to gauge more accurate and safe distances. You can also use this device for measuring the size that a particular area has and for verification of how sloppy a surface is in percentage grade. With this, you can be able to do spot checking of possible obstructions over a distance and confirm for any overhang clearances.   

The type of device used in this sector needs to be very rugged likewise it should be waterproof. It will be more helpful if its unit and your computer (laptop, etc.) can just integrate to allow for the direct input of all the measurements you’ve made into the construction software that you have installed on the laptop.  


In the mining sector, there is a need for precise measurement before blasting is done at all. With this, you will be able to accomplish optimal productivity from every mining section, and the safety of workers will be guaranteed. However, upon the development of rangefinders, the conventional methods used for this mining process when it comes to measurement are not allowed anymore.


In the airport, laser rangefinders are used for checking and measuring the runway and taxiway areas for safety as any present issues might be detected. Furthermore, the height as well as the slope of the lighting facilities and radio of the airport can be checked conventionally using this device.

Even in your runway, you can easily measure the distance lying between two distant/close objects. Meanwhile, you can easily inspect the airfield with this device as well. 


The prices of laser rangefinders often vary based on the uses and quality possessed by the device. The type of rangefinders used in the military must be very accurate at measuring and covering great distances. Their price could even span up to thousands of dollars, whereas the type used for civilian engagements like golfing or hunting is usually cheaper and can be easily accessed.


There are four existing classes of laser rangefinders and some other subclasses are also known. The types that are mostly used by consumers belong to either class 1 or 2, and they are regarded as the eye-safe types. Even though these types are rated as safe for the eye yet, avoidance of direct contact with the eye must be ensured. However, the military mostly makes use of rangefinders that are of energy levels that surpass that of class 2. 

Which Rangefinder Functions Should a Hunter Pay Attention to

There are many amazing functions that laser rangefinder performs in the course of hunting.

However, to choose a rangefinder for hunting is not so easy, but devices ought to be chosen based on the useful functions that can satisfy the interest of hunters, some of which may include:

  • Ability to make corrections using the Ballistic calculator, based on the standard of the device
  • Accuracy in measuring the distance of moving objects from its observer. 
  • Possession of angle meter which can be used in ranging angles. 
  • Ability to determine the speed with which the object moves.
  • The majority of the hunters out there often prefer using rangefinders of standard modes and functioning.

What is Beam Divergence

In case you’re wondering about how a laser rangefinder works concerning the beam divergence, note that it’s based on the focus quality that you obtain from the laser of your rangefinder. If you can reason out how the flashlight beam does spread as it moves further away from the source, then you will understand how beam divergence operates. Upon the spreading of a laser’s light, its reaction to more objects occurs progressively. If you want to focus on your target, you won’t want to see your beam diverging so much. Though, if your target is a big animal within a close range, then this issue of divergence might not be a serious thing. However, if your target is as small as a squirrel, then you will want your beam to work precisely. Besides, the more the beam is, so also the better the range of distance that you can see. 

What the Rangefinder Sees

While operating your rangefinder, the laser beam dashes out to hit your target once the appropriate button is pushed. In the course of this, just note that all you have been doing is sending out several lasers that are bounced off in the scope of the beam. All these processes occur promptly and your measured distance is displayed in no time. Some of these devices only measure the closest object’s distance on its way, but many other ones interpret its highest readings as the detected target. Some rangefinders will target object closest to it, while some will only target the farthest object. Some also have built-in specifications with which they can disregard any obstructing brushes between you & your target. Every one of the models interprets their data in different forms based on the programming of the device.  

A Different Angle

Just to hit on the points and not go deeper into geometry, a target at an elevated position can resultantly influence rangefinder’s calculation as it plays a particular role. In the sense that, the distance taken downhill to the bottom of a tree compared to the distance measured straight to the top of that same tree requires some mathematical calculations. But no worries for some rangefinders have been designed to personally calculate the angles measured. This can help golfers a lot since the distance ranging downslope between you & the green (field) can influence how you will swing

Putting it All Together

We believe this article must have given good clarity to the headline which reads; how does a laser rangefinder work. With the use of this technology, every form of inaccuracy will be removed when targeting an object. Whichever type of activities or sports you engage yourself, the use of laser rangefinders and necessary digital technology for distance measurement will consequently augment your experience. Remember, anytime you’re able to afford any of these devices, try and make a purchase so you can ease your stress of measurement and enjoy its feature of accuracy. After an experience, you will be able to select an appropriate device for any purpose you may need it for.