Guide to viewing optics. Everything you should know binoculars vs spotting scopes vs telescopes vs rangefinders

When picking the best viewing optics for you, it pays to be meticulous about certain specs and functions of each choice. If you’re just getting into recreational activities that require long-range optical gear, you’ll soon find out that there is a wide variety of them, and they all have many uses. There are rangefindersspotting scopesbinoculars, and telescopes, and within those categories, you’ll find subcategories of different shapes, sizes, and functions of each. For example, there are rangefinders for golf and rangefinders for hunting, infrared binoculars and night vision binoculars, angled and straight spotting scopes, and so on. Consequently, it’s no wonder why so many questions surface regarding the differences between these optics and which to purchase.  

Related Post: Binoculars Buying Guide? 

As hobbies that use viewing optics become more popular – like golfing, stargazing, wildlife observation, and birdwatching – the pool of optical gear will only become more saturated. Therefore, in response to the growing demand, we’ve compiled an easy-to-follow guide that explains the differences between each sight, its usage, and the different subcategories within a viewing optic. By the end of this post, you’ll know all about sight basics and essentials – giving you much more confidence in the field of optics.   

Binoculars vs Spotting Scope vs Telescope vs Rangefinder  

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what binocular numbers mean
Rangefinder vs Spotting Scope vs Telescope vs Binoculars

What Do Binocular Numbers Mean?  

First, let’s discuss what the numbers mean when understanding how different optical devices are labeled. While searching for suitable viewing optics, you may notice that some of the names will typically have numbers within them; this can include binoculars, monoculars, spotting scopes, eyepieces, etc.

Here are some examples:   

These numbers are very important to know when you’re deciding which sight to buy. They refer to two key specifications: magnification and objective lens size. It’s written out as “magnification x objective lens size.” For instance, in the Zeiss example above (10×25), the “10” represents the magnification, and the “25” represents the objective lens size. If you see two magnification numbers, such as the Vortex “11-30x,” this just means the magnification has a range of 11x to 33x.

The Magnification – indicates how much closer the object being observed appears to the naked eye. So (using the same example) the 10x magnification means that the object appears 10 times closer than it would to the naked eye. 

The Objective Lens Size – indicates the size of the objective lens or, simply put, the lens at the front of the optic that collects light. The objective lens size is measured in millimeters and determines how much light the viewing optics can gather. Therefore, the larger the objective lens size (or number), the brighter and more detailed the image is. 

Knowing this is an excellent start to understanding the performance of your sight. It is also important to realize that each feature has pros and cons, so knowing what you need most will determine the ideal sight you want. For example, is a higher magnification better than a low one? Well, if you want more detail and a closer look at long-range subjects, yes; however, this also means your sight will have a narrower field of view and will be harder to stabilize without a tripod (the more you zoom in). As for the objective lens, a wide lens will make the image much brighter, but it can also come at the cost of a heavier, more cumbersome optical gear. These are just a few things to keep in mind when considering which lens you should get.  

Universal Terms for Viewing Optics

Before looking at the different features and types of viewing optics available, here are a few essential terms you should know. These terms apply to most (if not all) optical instruments and refer to everything from their build features to important functions. Knowing these terms will help you navigate the world of sights more seamlessly and give you a better-established understanding of specs and observation terminology.

Optical Term Definition
MagnificationThe degree to which the object being viewed appears larger than its actual size
Objective lensThe lens on the front of an optical instrument that gathers and focuses light
EyepieceThe lens or group of lenses at the end of an optical instrument that is viewed through by the observer
Field of viewThe extent of the observable world that can be seen through an optical instrument
Exit pupilThe diameter of the beam of light leaving the eyepiece
Diopter adjustmentA mechanism that allows the user to adjust the focus of the eyepiece to their individual vision
Focal lengthThe distance from the objective lens to the point where the light is focused
Coatings Layers applied to lenses to reduce reflection, increase contrast, or improve light transmission
ZoomA feature that allows the user to change the magnification of an optical instrument
TripodA three-legged stand used to support an optical instrument for stable viewing
PrismA piece of glass or other transparent material used to reflect and refract light to produce a brighter, clearer, or corrected image
ApertureThe opening in the objective lens that allows light to enter
FocusThe ability of the optical instrument to produce a clear image at a specific distance or depth
ResolutionThe ability of the optical instrument to distinguish between fine details in an image
Image stabilizationA feature that reduces image blur caused by hand-held shaking
Eye reliefThe distance from the eyepiece to the observer’s eye
Twilight factorA calculation that estimates the optical instrument’s ability to gather and transmit light in low-light conditions
ParallaxThe apparent shift in the position of an object when viewed from different angles
ReticleA crosshair or other marking inside the eyepiece used for aiming or measuring

What are Spotting Scopes Best For? 

Spotting scopes are designed for observing expansive landscapes at various distances when locating objects or subjects. Spotting scopes are often great for bird watchers, hunting, wildlife experts or scientist, and other outdoor enthusiasts looking to survey surroundings. 

Angled Spotting Scope vs Straight Spotting Scope: Curved spotting scopes are more comfortable to use when looking upward or downward due to their 45º-90º angled eyepiece attachment. Curved spotting scopes are typically more compact and designed to help scan the sky during birdwatching; they pair nicely with tripods. Straight spotting scopes are more suitable for wildlife observation and quick acquisition of eye-level subjects.

Spotting scope vs telescope: Both these viewing optics share similar designs; however, most spotting scopes are much smaller, compact, and portable. They often have a wider field of view than telescopes, making them well-suited for observing large areas. Spotting scopes usually have a magnification level between 20x and 60x and are relatively versatile. As for telescopes, magnification can range from 30x on the low end to 500x or even greater. In short, spotting scopes are portable and designed for terrestrial observations, while telescopes are larger and designed for astronomical observations

Spotting Scope vs Binoculars: Spotting scopes are larger, heavier, and more specialized optics used for longer-range observation than binoculars. They’re usually mounted on a tripod for birdwatching, hunting, wildlife observation, and target shooting. Spotting scopes have a higher magnification range than binoculars, giving you greater detail and clarity when observing distant objects. Lastly, spotting scopes have a narrower field of view, making them better suited for stationary or slow-moving objects, and may have interchangeable eyepieces, allowing for more versatility in magnification.

Different Types of Spotting Scopes? 

When understanding which spotting scope to buy, it first helps to know the different types of spotting scopes and each main purpose. Some spotting scopes are designed specifically for birdwatching, with features such as a close focus distance, a wide field of view, and a durable, waterproof design. Other spotting scopes are designed for hunting, with features like camouflage patterns, low-light performance, and durable builds. Here’s a list of a few different types of spotting scopes and functions:  

Spotting scope for birdwatching: These spotting scopes are specifically designed for bird watchers and birding enthusiasts. They usually have a relatively low magnification level, between 15x to 30x, and a large objective lens size of around 60mm to 80mm to provide a wide field of view. They may also have features such as close focus capability, weather resistance, and image stabilization to allow for precise and steady viewing of birds in their natural habitats. 

Spotting scope for hunting: Hunting spotting scopes are made for hunters and outdoors enthusiasts who need to observe wildlife from a distance. They may have higher magnification levels, up to 60x or more, to allow for clear viewing at long distances. They may also have camouflage coatings, shock resistance, and waterproofing to withstand rugged outdoor conditions. 

Spotting scopes for astronomy: These spotting scopes are for stargazing and celestial objects. They usually have a high magnification level, up to 100x or more, and a large objective lens size of around 80mm to 100mm to gather as much light as possible. They may also have features like motorized tracking systems to follow celestial objects and specialized filters for viewing the sun. 

Tactical spotting scopes: Tactical spotting scopes are designed for military, law enforcement, or other tactical use. They may have features such as rangefinders, reticle systems, and illuminated optics to aid in targeting and ranging objects at a distance. They may also have durable construction and shock resistance to withstand harsh environments. 

Marine spotting scopes: These are designed for use on boats or in other aquatic environments. They may have waterproofing, corrosion-resistant coatings, and anti-fogging properties to withstand exposure to saltwater and other elements. 

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Rangefinder vs Spotting Scope vs Telescope vs Binoculars, viewing optics

What are Binoculars Best For? 

Binoculars are the most common viewing optics on this list and are exceptional for a variety of users, from beginner to advanced. Binoculars are essentially two miniature telescopes mounted side-by-side that allow you to view distant objects with both eyes instead of one, unlike spotting scopes or monoculars. They’re great for different hobbies and activities like birdwatching, spectating sporting events, boating, observing astronomy, sightseeing, and traveling. 

They have a vast range of magnification levels and objective lens sizes, which determine their overall size and weight. They are typically compact and portable and have a wider field of view than spotting scopes, which makes them ideal for scanning large areas or following moving objects.

Binoculars vs Monoculars: Binoculars use a double telescope, while monoculars only use one. Binoculars have a wider field of view and are easier to use than monoculars, and are considered a more comfortable and stable viewing experience. Binoculars also offer greater depth perception, making them ideal for birdwatching, hiking, and wildlife observation activities. Monoculars are smaller and more compact than binoculars, making them better for concerts, theater performances, or similar indoor events. Monoculars are more difficult to operate than binoculars because of the fact you hold them steady with one hand while focusing with the other. Not to mention, their lack of depth perceptions compared to binoculars, takes away from detail and accuracy.

Binoculars vs Spotting Scopes: Binoculars and spotting scopes can often overlap for activities like birdwatching, astronomy, and wildlife observation. However, you might find binoculars a better viewing experience for mobile ventures like camping, hiking, sporting events, and concerts due to their smaller and more portable size. Binoculars have a wider field of view, making them ideal for observing objects in motion or moving quickly. Spotting scopes often have higher magnification ranges, a narrower field of view, and provide more detail at longer distances. They’re usually paired with tripods more often and are great for long-range target shooting, hunting, and far observations.  

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How are Binoculars Classified or Grouped?  

There are many different types of binoculars and endless ways to group them. The most common methods of classifying binoculars are by their intended uses/designs, optical specifications, or prism type. “Intended use” means looking at what practices a binocular is designed for, such as birdwatching binoculars, hunting binoculars, marine binoculars, astronomy binoculars, and compact binoculars, often implied by its manufacturer.

As discussed at the beginning of this post, it’s common to identify optics based on their (magnification and objective lens) specs or, put simply, the numbers within their names. As a refresher on what the binocular numbers mean: the “magnification” is the first number and refers to how much closer the object will appear when viewed through the binoculars. The bigger the magnification number, the farther out you can see your subjects. As for the “objective lens,” it’s the front lens of the binocular that collects light; the wider the lens (or bigger the number), the more light it can intake, giving you a higher resolution and a brighter image.

Lastly, you can group binoculars by “prism types,” such as roof prism vs Porro prism. The prisms are located within the binoculars and reflect the magnified image right side up between the glasses, so you’re not looking at an upside-down picture. All you really need to know is that “roof prism” binoculars are more compact, durable, usually higher priced, and tend to lose light and clarity due to their straightforward interior design. While “Porro prism” binoculars have a zig-zag interior glass design that helps to produce a higher quality image because of less drop-off in light, they are less durable and are usually bulkier. 

binoculars for birding, safari, sports, viewing optics, guide for sights and optics

Different Types of Binoculars?  

Birdwatching binoculars: These binoculars are designed for birdwatchers and nature enthusiasts. They typically have a high magnification level (between 8x to 10x) and a large objective lens diameter (32mm – 42mm) to provide a bright and clear image of birds in their natural habitats. They may also have a close focus capability and a wide field of view to help track birds in flight. 

Hunting binoculars: Hunting binoculars are designed for hunters and outdoor enthusiasts. They usually have a high magnification level as well and a large objective lens diameter (40mm – 50mm) to provide detailed images of game from a distance. They may also be waterproof, fog-proof, and shock-resistant to withstand rugged outdoor conditions. 

Marine binoculars: Marine binoculars are mainly designed for boaters and sailors. They’re primarily waterproof and may have a handy built-in compass for navigation. They typically have a magnification level between 7x – 10x and a large objective lens diameter (25mm – 50mm) to provide a clear view of distant objects on the water. 

Astronomy binoculars: Binoculars for stargazing make for enjoyable celestial observation sessions. They typically have a high magnification level (10x – 25x) and a large objective lens diameter (50mm – 70mm) to gather large as much light as possible during the night. They may also have a tripod adapter for steady and more comfortable viewing. 

Compact binoculars: Compact binoculars keep portability and ease of use at the forefront of design. They typically have a small objective lens diameter (20mm – 25mm) and a magnification level of 8x or less. They are ideal for hiking, travel, and other outdoor activities where packing space is limited. 

Image-stabilized binoculars: Binoculars with image-stabilizing features have built-in mechanisms that reduces image shake and provide a steady view even at high magnification levels. They are ideal for birdwatching, hunting, and other activities where a stable image is essential. 

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how do optics work
what binocular numbers mean
Rangefinder vs Spotting Scope vs Telescope vs Binoculars

What are Rangefinders Best For? 

Rangefinders are viewing optics used to measure the distance between the observer and their specific target. To accurately determine that distance, rangefinders magnify what you are looking at and use either lasers or sound wave technology that emits toward the target to tell you the space between. Rangefinders are commonly used for hunting, golfing, and other outdoor activities where precise distance measurement is essential. Some rangefinders also have additional features, such as angle compensation or ballistics calculators, which helps the user make more accurate shots. Angle compensation, as it sounds, helps account for the angle of your target and the distance, which is very beneficial as the measuring space gets further. Ballistics calculators help to consider more in-depth environmental factors that can also affect your shot, increasing your chance of success.

Hunting Rangefinder vs Golf Rangefinder: Hunters use rangefinders to determine the distance to their target for a more accurate shot. Golfers use rangefinders to measure the distance to the green or other hazards on the course, which is crucial for excellent ball placement.

Rangefinder vs Binocular: It’s interesting to note that some binoculars may have built-in rangefinders. However, the primary function of binoculars is not distance measurement, and therefore they may not provide as accurate readings as a dedicated rangefinder. 

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Different Types of Rangefinders 

Laser rangefinders: These are the most common type of rangefinders. They work by emitting a laser beam that bounces off the target and back to the rangefinder, allowing it to calculate the distance. 

Golf rangefinders: These rangefinders are specialized for golf courses and often have unique features such as slope compensation, which adjusts the distance based on the angle of the slope. 

Hunting rangefinders: These rangefinders are built for hunters and often have features such as a “scan” mode that allows them to continually update the distance to a moving target. 

Archery rangefinders: These rangefinders are specifically designed for archers and typically have features like angle compensation, which, as mentioned can account for the angle of the shot. 

Ballistic rangefinders: These rangefinders are designed for use by long-range shooters and can calculate features such as bullet drop compensation and windage adjustment. 

Optical rangefinders: These are a type of rangefinder that uses an optical system to measure distance rather than a laser. They are less common than laser rangefinders but are still used for things like surveying. 

What are Telescopes Best For? 

Last but not least, there are the famous and astronomy-friendly telescopes. Telescopes are long-range optics mainly used to observe objects in the night sky, such as stars, planets, comets, and more. They come in various sizes and designs, from small, portable models to large, permanent observatories. Some telescopes are designed for simple visual observation, while others are intended for astrophotography or other types of imaging.  

In addition to classic telescopes, there are also smart telescopes with extended capabilities to give you an enhanced observation experience. Smart telescopes possess features like self-alignment, which uses GPS and built-in sensors, so beginners don’t have to do it manually. They can also map out the stars, adjust settings using a smartphone or tablet, capture images, and offer augmented reality features; making them much more advanced than binoculars, spotting scopes, or rangefinders.  

The magnification of a telescope depends on both the focal length of the telescope and the eyepiece being used. The magnification range of commercial telescopes can vary greatly depending on the type and size of the telescope and the eyepieces used. Generally, the magnification range can be anywhere from 20x to 500x and beyond. However, it’s also important to note that higher magnifications do not necessarily equate to better views of the night sky. In fact, a magnification too high can result in a dim and blurry image.

Telescope vs. Spotting Scope: Telescopes have a longer focal length and a more narrow field of view than spotting scopes, allowing telescopes to magnify distant objects in the sky easily. Telescopes also have a much larger objective lens due to their need to capture high amounts of light to produce detailed images in low light. Both observation instruments are commonly used with tripods; spotting scopes are much more compact and portable, often with a straight or angled body, while telescopes are larger and heavier.

Different Types of Telescopes 

Refracting telescopes: Refracting telescopes use lenses to gather and focus light. They are the classic telescopes that most people are familiar with, with a long, narrow tube and a lens at one end. They are typically suitable for viewing objects in the solar system such as the moon, planets, and stars. 

Reflecting telescopes: Reflecting telescopes use mirrors to gather and focus light. They are usually more compact than refracting telescopes and are better suited for viewing deep-sky objects such as galaxies, nebulas, and star clusters. 

Catadioptric telescopes: Catadioptric telescopes combine lenses and mirrors to gather and focus light. They are a hybrid between reflecting and refracting telescopes and can be more expensive than either type. They’re very compact and portable and are well-suited for astrophotography. 

Radio telescopes: Radio telescopes use radio waves to detect and study celestial objects. They’re normally enormous and expensive, and are used for research and scientific study rather than casual observation. 

X-ray telescopes: X-ray telescopes use mirrors and detectors to capture X-rays emitted by celestial objects. They are typically used for research and scientific study, as X-rays are not visible to the naked eye and require specialized equipment to detect. 

Solar telescopes: Solar telescopes are made for observing the sun. They use special filters and lenses to protect the observer’s eyes from the sun’s intense brightness and are used for studying solar flares, sunspots, and other solar phenomena. 


That concludes our general overview and guide to viewing optics basics and essentials. Though each optic has its own unique purpose, they can often overlap with one another when it comes to functions, features, and usage. It’s important to know which features you’ll need the most to select the most suitable optics, from the physical build and visual quality to the field of view, magnification, and even stability. Hopefully, this guide will help you to understand not only the different features between each viewing optic but also their subcategories and specific capabilities. Test your new knowledge by exploring thousands of optics and scopes today designed by popular optics brands.

What type of viewing optics do you prefer, and for what activities?



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