Binoculars are two telescopes mounted on one frame and used to view distant objects through magnification, according to Encyclopedia Britannica. A monocular is one telescope used to view distant objects. The main difference between the two is that you view with a monocular using only one eye; both eyes are used with binoculars.
Monoculars are small enough to fit in your pocket but can provide magnification as strong as that provided by binoculars. The size of the lens determines the size of the monocular--a tool commonly used for birdwatching, golf and military activities. Monocular is a term that also applies to the viewers used in microscopes and telescopes. The first monoculars were used as telescopes, and most monoculars in use today are found in microscopes and telescopes.
Binoculars are more commonly used because they allow you to view in a more natural and comfortable way. They give depth perception and better visual acuity as you do not have to close one eye to see through binoculars. Due to this better range of vision, binoculars are used to follow movement, as with sporting and racing events.
Tips for Use
Monoculars in basic form are just point and view tools. You focus by rotating the body of the monocular. Some have special features like night vision--and such features require batteries. Binoculars have a dial between the barrels for focusing. Users should focus on a stationary object before trying to view a mobile object in the same range.
Magnification is measured with two numbers. The first number is the actual magnification, and the second number is the lens diameter. For example, 7 x 50 indicates that objects will appear seven times closer and the lens is 50 millimetres in diameter. Some monocular and binoculars have power zoom, and this is represented with two numbers at the beginning, 10-30 x 50.
Deciding between a monocular or binoculars depends on the intended use. A monocular is small and lightweight. Binoculars give you more range of vision and allow you to follow movement. A monocular can cost anywhere from £13 to more than £195 depending on the power of magnification and added features. Binoculars can cost from £19 to more than £1,300.