Binoculars Guide

What Are Binoculars?

Binoculars are a pair of identical or mirror-symmetrical telescopes placed side by side (one for each eye) and aligned to a point accurately in the same direction. Most binoculars are built to be hand held, although sizes vary widely from super compact opera glasses to large tripod mounted mounted military ones. They are used for a variety of purposes with the single intention of seeing a far distance in closer detail. Due to the different uses of binoculars, binoculars will vary in different features to best cater to these uses. These factors may include magnification, objective lens diameter, waterproofing, tripod mount, lens coatings and more.

What Do The Numbers Mean?

What Do These Numbers Mean?

Magnification (Power)

Objective lens (Diameter)

The first number "7" is the power of magnification that the binoculars offer. With "7x" magnification, you'd see things 7x closer than your normal vision.

There are also zoom binoculars. They have variable magnification power. 8x is the main magnification power with the optimum performance. The 16x maginification won't provide brighter and better quality image because the objective lens at the front can't change to follow the magnification power increase.

7x magnification is often chosen by most because it is easier to handle. The higher the magnification is, the more sensitive it is. A little tremble from your hand would feel like a big shake. If you prefer something bigger than 7-8x for a long use, it is recommended to use a tripod. If you have a high powered pair of binoculars with small objective lens, they are better for day time use as a simple aid to see farther.

The second number is the diameter of the objective lens in millimeters.

Large objective lenses are great for light transmission. Large numbers = larger binoculars.

Depending on what your binoculars will be used for, you'd want to find the right one (in terms of size, power and brightness).

Popular Standard Binoculars

Bushnell Engage EDX 8x42 Binoculars

Vortex Viper HD 8x42 Binoculars

Zeiss Conquest HD 10x42 Binoculars

Steiner Skyhawk 4.0 10x42 Binoculars

Types of Binoculars

There are 2 types of binoculars based on the prism design: Porro Prism Binoculars & Roof Prism Binoculars. Porro Prism binoculars are known to produce brighter images and roof prism binoculars are known for being compact and more durable.

Pros

Usually more compact compared to similar porro-prism model.
Easier to hold.
Generally tougher than porro prism binos of the same specification.

Cons

Tend to be more expensive.

Pros

Affordable and provides very good optical quality.

Cons

Generally not as compact (except for inverted porro design).
Less comfortable to hold for a long time.

Lens Coatings

Coated		Fully Coated		Multi-Coated		Fully Multi-Coated
A single layer of anti reflection coating is applied to some elements of the lens.		All air to glass surfaces are coated.		Some surfaces have multiple anti-reflection coatings.		All glass surfaces have multiple coatings.

Prisms Grade

Prisms direct light path inside the binoculars. There are two types of prisms commonly use for binoculars.

BaK-4 - Created from Barium Crown Glass. Considered as the superior prism because it has better light transmission.
BK-7 - Created from Borosilicate Glass. Good light transmission and more affordable.

Popular Roof Prism Binoculars Popular Porro Prism Binoculars

Bushnell Spectator Sport Focus-Free 7x35 Binoculars

Steiner Commander 7x50 Marine Binoculars with Compass

Leica Trinovid HD 10x42 Binoculars

Zeiss Conquest HD 8x42 Binoculars

Bushnell Spectator Sport 7x35 Binoculars

Steiner Commander 7x50 Marine Binoculars with Compass

Binoculars & Activities

Activities	Recommended Binoculars
Birding	8x40, 8x42, 10x42, 10x50	It is recommended to get a waterproof, rugged, high quality pair of binoculars that you can use in any environment. You will also want lightweight binoculars as you will likely hold them up for long periods of time.
Hunting	10x42, 7x50, 8x40, 8x42, 10x50, 12x50	For greater distance hunting: 10x42, 8x40, 8x42, 10x50, 12x50 would have a nice balance of magnification and exit pupil. For low light hunting: 7x50, 8x42.
Travel, Backpacking, Hiking	10x25, 10x26, 8x21	Generally very lightweight and compact binoculars are the preferred option for convenience. As you will likely be holding a lot of things with you, the lighter the binoculars, the more likely you'll take them with you!
Sports Viewing	8x25, 10x30	Moderate power and wider angle of view is what you need (8x-10x compacts). Compacts are also very popular for spectator sports.
Theatre / Opera	3x25, 5x17	Compact binoculars with 3x-5x magnification power are great for theatre use due to the close proximity between yourself and the stage.
Astronomical	7x50, 8x56, 9x63, 20x80	For handheld use, 7x50, 8x56, and 9x63 would be sufficient. For a stable and long usage, a 20x80 or a 25x100 on a tripod is ideal.
Surveillance	7x50, 8x42	A exit pupil is desirable for night surveillance. 7x50 is the standard for most navvies around the world and 8x42 is a popular configuration with other law enforcement agencies.

Other Features

Exit pupil	The size of an exit pupil shows the amount of light that you'll get. Of course, more light means brighter image. You can calculate it if you like: Objective Lens diameter / Maginifcation = Exit pupil. So, with our binoculars above, we'd get 50/7 =7.1mm. On average human eyes, pupils dilation have the capability to go up to 7mm. With 7.1mm, you can see very well in low light condition. Exit pupil= objective lens / magnification power
Twilight Factor	Twilight factor determines resolution, the higher it is the better the resolution. If you'd like to calculate this, just multiply the maginification power and the objective lens, squre root the result and you'll get the twilight factor. Twilight factor = √magnification power x objective lens
Luminosity	This factor determines how well the binoculars perform in low light. To calculate this, divide the aperture or objective lens diameter by magnification and square the result. The higher it is, the brighter the images in low light conditions. Luminosity = Exit Pupil²
Field of View	How much of the area can you see through your binoculars? It's important for birders and hunters to follow movement of the subject. It is also great for binoculars used at sporting events.

If you need any more help choosing the right set of binoculars for you, don't hesitate to contact our friendly team - our details can be found here.