How do Rangefinders Work?

Everyone knows that a rangefinder is a very handy device for measuring distance, but how exactly do these nifty devices operate? There are actually a couple of different ways that rangefinders use to measure the distance towards whatever it is pointed at, but the most common is lasers. While it is not necessary to understand how rangefinders work in order to use them, some familiarity with the concept will come in handy in the field. This information can also help you to use your rangefinder in a more skillful manner.

As anyone who have used a laser rangefinder can attest, it is very straightforward to use. You simply point the rangefinder at whatever object you want to measure the distance to and press a button. What happens when you press the button is that the rangefinder emits a laser beam which then bounces off the object before returning to the rangefinder. The rangefinder is equipped with a very high speed clock which then measures the time that elapsed between emitting the beam and it returning. The laser beam obviously travels at the speed of light which is a known constant, so the rangefinder then uses a formula to calculate the distance based on the time it took for the beam to return.

Of course, if the process was that simple all laser rangefinders would produce the same accurate results which is unfortunately not the case. Despite using the same method to calculate the distance there are certain rangefinders that are better and more accurate thanks to their construction. The quality of the optics and the magnification level are two very important factors that influence the effectiveness of rangefinders. After all, how do you calculate the distance to a target if the target isn’t visible? A high magnification level enables you to find more targets, but the glass quality of the scope also has a huge impact.

Since the laser beam has to return to the rangefinder in order to gain a reading the receiver aperture size is another important component. Simply put, a larger aperture allows for more data to be collected by the rangefinder which effectively increases its range capacity. Even at shorter distances a larger aperture size means better resolution and measurement accuracy.

As technology improved so has the method which laser rangefinders use to calculate distance. Unlike older models that displays the first reading received by the unit, modern ones employs something called multi-pulse technology. Instead of a single laser pulse the rangefinder instead a burst of pulses and then analyzes the results to produce a more accurate reading.

In order to increase their usefulness to hunters some rangefinders pack additional features such as an inclinometer or ballistic calculator. Information such as the angle of the target and bullet drop calculations can mean the difference between a clean kill and wounding an animal making them very important. Bow hunters in particular can benefit immensely from the extra information that rangefinders are able to calculate which is why many models include the ability to switch between rifle and bow modes. The information is typically displayed on a through the lens LCD although OLED displays are also available at higher price points.