A rangefinder has many different applications in the world today. The range finder measures the distance between to points for surveying, determining the focus for a camera, aiming a weapon or determining the correct club in a golf shot. There are three basic types of range finders, one uses optics and triangulation, another uses various waves and reflection and the third uses waves and triangulation.
There are three types of reflection rangefinders. A laser rangefinder works through the process of reflection. A laser beam is bounced (or reflected) off of an object and returned to the unit. The time it takes for the laser beam to return is converted into a distance measurement. Since the measurement is based on the reflective nature of an object, a highly reflective object such as a metal door can be measured from a greater distance than a tree which is less reflective. There are many models today that can accurately measure reflective targets up to 1500 yards away and are accurate to within one yard.
A sonar rangefinder works in a similar fashion as the laser rangefinder except sonar bounces sound waves off the object. A radar rangefinder bounces radio waves off the object.
An optical rangefinder is mechanical and uses triangulation to measure the distance from one point to another. The rangefinder has an eyepiece that gives the user two images of the object being measured. The eyepiece is then turned in such as way so that the two objects become one. Once that is accomplished, the distance can be read off a scale on the adjustment control. This is the basic technology used in the rangefinder cameras in order to keep the photographed subject matter in focus. Since this type of rangefinder is calibrated to measure the movement of a mirror inside the eyepiece, it is only accurate to within 5 yards under 100 yards and within 10 yards at 500 yards. For this reason, this type of rangefinder is not suitable for a golfer or a bow hunter.
GPS Range Finder
The GPS rangefinder uses the Global Navigation Satellite System to measure the distance between two points by determining their exact location on the earth. GPS rangefinders can determine distances to fixed location to within an inch if properly calibrated.
There is a plethora of rangefinders for sale by a few companies for application in golf and hunting. For golf range finders there are many different features available. Some display yardages to different points as you scan across the landscape. Others compensate for the slope of the hole and adjust the yardage required accordingly. Some of the rangefinders are okay to use in tournament play and others are not. Some rangefinders are designed to lock onto the pin so that it can measure the distance from the player more accurately. GPS range finders for golf also have many different features as well. Some calculate basic statistics, keep your score, and show different distances to major obstacles.
Hunting rangefinders have many of the same features as the golf range finder except the display if different. Instead of slope the device measures the degree of vertical tilt to provide the true horizontal distance to a given target. Some models are camouflaged so you can hide in the brush to seek your prey.
This site reviews the different types and models of rangefinders and discusses their features in terms of its effectiveness in the application required.