Function of a Rangefinder
Rangefinders send an invisible laser pulse that reflects off of distant objects with the push of a button. The rangefinder has a digital clock that measures the time taken for the beam to bounce back from the object and calculates the distance to the object with very good accuracy, typically within 0.5 yards. The larger the object, the further out the rangefinder can function. For example, if you are ranging a rabbit, a rangefinder may only work out to a few hundred yards. However, if you are ranging an elk, the rangefinder will be able to function at a further distance. The whole process is extremely fast. Many rangefinders are water resistant and work well in less favorable conditions. The magnification of a rangefinder varies from unit to unit, but are typically in the 6x - 8x magnifaction range. Like binoculars
, they can be operated with one hand.
Sensing and Accuracy
The accuracy of a rangefinder is often down to less than 1 yard. Most exenpsive models can be accurate down to 0.1 yard.
Typically, the greater the distance being measured, the less accurate the measurement, than a measurement. The maximum distance
of a modern high-end rangefinder is around 2,000-3,000 yards. Rangefinders are usually used for hunting, shooting, golf, and other sports. As you might expect, the more expensive the rangefinder, the more accurate it typically is. Higher end rangefinders will also come with more features and are typically more durable that lower end units.
The magnification of a rangefinder determines how much closer an object appears to be. A rangefinder
with a magnification of 6x will display an object that is 600 yards away as if it where only about 100 yards away. Range finder magnification varies, but are generally between 3x and 8x. There are binoculars with built-in rangefinders that have magnifications between 10x and 15x. As you might expect, these rangefinders will also cost more.
A range finder's lens diameter is the size of the glass lens in front of the meter. Monocular rangefinders designed for hunting or golf usually have a smaller lens diameter of around 20 - 26mm. Larger binocular rangefinders may have the same size lens diameter of conventional binoculars.
Binocular rangefinders are often expensive because the design and technology is rather complex. Generally speaking, a larger lens diameter
provides the rangefinder with greater light gathering capability and thus are better used for low light conditions such as dusk and dawn.
Coating lenses on a rangefinder varies from brand to brand and model to model. The more expensive models from brands such as Zeiss
typically have the finest finish on the market. The type of surface treatment used affects light transmission of the rangefinder. A surface treatment in multiple layers of high quality product can produce a brighter and
more contrasting image. It can also determine how the lenses manages
moisture, water droplets, dirt and dust. Many rangefinders in the higher price range have a water repellent and
stain resistant coating, which prevents the oils and dust from collecting.
Field of View
A rangefinders visual field of view differs primarily with the magnification and lens diameter. A smaller magnification
gives a wider field of view. Likewise, a greater lens diameter offers a larger and broader field of view.
For a compact size of a rangefinder, the field of view is often limited as its primary function is to measure the distance of an object in the distance. Binocular/rangefinder combos have a wider field of view due to their larger lenses. This gives them a field of view which is fully comparable to a set of binoculars. However, expect to pay a lot more for the binocular/rangefinder combo.
Water Resistant/Moiture Barrier
Most rangefinders are water resistant. Some are even nitrogen filled, similar to binoculars,
to prevent internal condensation. More expensive rangefinders often offer very good water protection. Less expensive rangefinders vary
from model to model. It is important to be aware that water damage is not covered under a manufacter's warranty unless the model is marked as water-proof. Water resistant only means that the item can handle slight moisture and generally should not be used in wet conditions.
Size and Weight
A range finders size and weight is determined primarily by the objective lens size, and whether it is a
monocular or binocular. The larger the lens, the heavier and larger it will be. If you will be using your rangfinder for golf or hunting, it is often more practical to use a more compact one. That way you can more easily operate it with one hand and store it more readily. These rangefinders often weigh less and its size is such that the unit can easily be held and operated with one hand.
Larger rangefinders are often cuppled with binoculars. They typically have a larger lens diameter and multiple eyepieces.