How Do Rangefinders Actually Work

Rangefinders measure distances between targets and the observer. In the past, distances to targets were estimated using known information such as premeasured distances and/or average target sizes. Today, technology can reduce the amount of guessing required to distance objects. Typical consumer rangefinders are of the handheld laser variety, which use (you guessed it) lasers to calculate distances. So you might ask yourself how do rangefinders work, anyway?
So How Do Rangefinders Work?

To calculate the distance between observer and target using lasers, some information must be gathered by the device. By knowing the speed of light and calculating the amount of time it takes for the laser’s light to be generated, bounce off objects in the distance, and then return to the rangefinder’s sensor, the distance between the two points can be quickly calculated.

For those curious enough to ask, calculating these distances is done by multiplying the speed of light in air, which is an astonishing 186,225 miles per second, by the time for light to travel, in seconds, to the target. The time light takes to travel to and from the target is, therefore, incredibly short. To range an object 1/2 a mile away, light travels to and from the object in 1/186,225th of a second.

The distances measured wind up being shorter than thousands, or even hundreds, of kilometers or miles. We wind up with measurements of distances between a few, to a couple thousand, meters or yards; perfect for ranging a target while hunting or golfing. However, the ability of a rangefinder to measure distances is not constant.

1. What Influences Rangefinder Accuracy?

The ability of rangefinder sensors to read the returning light from their own lasers is also affected by factors other than the distance to the targets. How reflective the target surface is also plays a critical role in determining how far the rangefinder will work. An aluminum shed in a field can be distanced considerably farther than a deer in the woods, regardless of the rangefinder’s quality. However, the shed’s ability to reflect light is not the only factor in play in this example.

Besides how reflective a target is, the rangefinder’s ability to distance may also be determined by how large the target itself actually is. The further away the target, the less-focused the rangefinder’s beam will be on contact (here’s some difficult-to-read content on that matter). As the beam loses focus, larger targets are needed to reflect adequate light for most rangefinders to detect.  More accurate, longer-distance rangefinders have lasers which are more focused than others, and they are therefore less susceptible to this issue.

So, if you’re in the market for a rangefinder, you might notice that there are several varieties that exist. It is important to note that not all rangefinders are alike, and many have special use-cases that make them more appropriate for certain distancing tasks. For example, archery rangefinders, meant for hunting, would not necessarily be adequate for golfers looking to measure the distance to their flags. Also, golfing rangefinders may not be appropriate for hunters searching for deer obstructed by bushes or trees. You might ask “Why?” To answer that question, we have to look deeper into how rangefinders find their targets.
They’re Mini Computers!

2. Rangefinders are like computers

Rangefinders are more than just lasers and distance calculators. They are miniaturized, specialized computers, built to accomplish very specific tasks. Golfing rangefinders, for one, have been adapted to pick out the closest targets among clusters of many different targets; this allows golfing rangefinders to focus on that flag off in the distance, instead of any other objects that might be further in your line of sight. Likewise, hunting rangefinders may focus on the objects furthest away in your line of sight, enabling you to find a more accurate distance of that buck hidden within the trees and bushes. There are also archery rangefinders, which come with the added benefit of calculating true horizontal distances and angle compensation — great to know what pin is appropriate when shooting from a tree or lookout or when accounting for bullet drop. There are several different prioritization methods rangefinders may use to determine their targets, and these priorities determine whether the rangefinder in question is up to any given distancing task. So besides just wondering “how do rangefinders work,” you should also ask yourself “how to rangefinders prioritize my target?”

Today’s higher-quality and more expensive rangefinders may include adjustable settings to switch their mini-computers between golf, archery, and hunting methods of target-acquisition. The different methods by which these multi-use rangefinders can calculate distance make these tools adaptable and incredible. Also, among all the rangefinders on the market, you will find a wide range of accuracy from a few yards to within tenths of yards, and their maximum distancing abilities range from low hundreds of yards to thousands of yards. The higher-quality rangefinders will of course pack higher accuracies with greater distancing abilities.

3. So What Do Rangefinders Mean For Me?

If you’re a hunter or archer, you’re already more than familiar with bullet drop and/or accommodating for distance in your shots. Any hunter or archer can benefit from having the most accurate estimate of their distance to their targets possible.  If you’re a golf enthusiast, you may have noticed that rangefinders are not used by the pros at tournaments. The debate of whether rangefinders should be allowed in professional golf tournaments has been fought for years, with supporters of traditional game play concerned for the integrity of the game and supporters of rangefinder technology enjoying the boost they provide to game pace. Regardless of the professionals’ stance on rangefinders, these nifty little handheld devices are becoming more and more acceptable for, and popular among, amateurs over the years.

When it comes to choosing which rangefinder would best meet your needs, you should take the time to consider what you primary use of the rangefinder will be. Whether you’re going to be using the rangefinder on a golf course and really want to know an accurate distance to your next hole or if you’re going to be bow hunting from trees, you should definitely search for rangefinders which are up to each specific task. We hope knowing exactly “how do rangefinders work” will help you pick the right one for your needs.

How Do Rangefinders Actually Work
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One Response to How Do Rangefinders Actually Work

  1. The genious boy July 12, 2016 at 1:43 pm #

    I don’t like them personally but they are a nice and expensive piece of equipment, but i never asked myself how they work, thanks for the enlightenment!

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