A monocular is a single-barrel refractor viewing device for looking at objects in the distance. They are usually more portable and smaller than spotting scopes and are widely used by bird-watchers, airplane spotters, hikers and walkers, hunters and amateur astronomers.
Images of objects in the distance are magnified in a monocular by use of a series of lenses or prisms. A monocular products two dimensional images, unlike binoculars which produce three dimensional images.
Monoculars are relatively cheap to buy compared to most other viewing devices including the telescope, spotting scopes and top quality binoculars. There are plenty of monoculars under £20 but prices rise much higher for monoculars with stronger magnification and other features like night vision.
You can determine the magnification level of your monocular and any visual aid by looking at the first number of the mutual X-number equation which is present on any piece of optical equipment. For instance, if a certain monocular is 10×50, the magnification is 10.
This means that the magnification will show you a 10 times enlargement of the image which would be viewed with a naked eye. The object aperture of the monocular is the second number of the common equation. So, for instance, if this is 10×50, then the aperture is 50.
The aperture is the measurement of the diameter of your objective lens, and the objective lens depends on its size controls of how much light is apparent when viewing. The bigger the lens, the more light it reflects off the object, thereby making the image appear brighter, more helpful hints.
Lastly, the field of view of the monocular is the perceived width of the object image from 1000 yards away. It is important to note that the larger the field view, the lesser the magnification, and equally, the higher the magnification, the lesser the field view.
The lens in a monocular causes light entering it to bend. Light which enters the top of the objective lens will be bent downwards whereas the light at the bottom of the lens will be bent upwards. The crossing of the light beams causes a flipping of the image. This is counteracted to enable correct viewing by the eyepiece lens – light passes through this before hitting the eye to show the image right way up.
A monocular is a bit like a low powered mini telescope and more expensive models have night vision capability which is useful for studying nocturnal creatures. Night vision monoculars and spotting scopes are widely used by hunters and astronomers. Night vision devices are also widely used by the military and a night vision monocular can be mounted to a firearm and used as a night sight.
When you first use a monocular it is important to ensure you have a clear view of the object you are intending to watch. You should hold a monocular reasonably close to your eye, although not touching it, and if you wear glasses it is advised that you rest them gently against the rubber end of the monocular.
When you have lined the monocular up properly with the eye’s pupil you will see light appear. A monocular can be focused by placing a hand on the device’s ridged section and turning it slowly to focus the image. If you notice that the image has become blurred this means that the ridge has been turned too far and should be turned in the opposite direction to correct the problem.
Magnification is an important aspect of a monocular or any other viewing device – the greater the magnification, the more you’re likely to pay for a monocular or spotting scope. You should carefully consider exactly what you intend using a monocular for – there’s no point buying a very expensive one with a high magnification level if you intend to use it for viewing objects which are not particularly far away. A cheap monocular with 8x or 10x magnification level may be ample for your needs.
You should also give consideration to the subject of eye relief when buying a monocular. This relates to the distance that you can hold the monocular from your eye and still see the full field of view – some people will need to use a monocular at very short notice, for example if a bird or wild animal appears suddenly, so they will require a device which can be held up quickly a few centimetres from the eye. If you wear glasses it is important to ensure you buy a monocular which has an eye relief distance of 14mm or more to allow for the fact glasses will not allow you to get your eye any closer to the device.
Lens coatings are another important aspect of a monocular and affect image brightness. The best monoculars available to buy are fully multi-coated, multi-coated being the next highest models, and fully coated the least.
Many monoculars are waterproof so that’s certainly worth bearing in mind if you plan to use one in a wet climate or on board a ship, boat or other river or sea vessel.
If you don’t need a very high-powered monocular, a small pocket-sized one will probably meet your needs. These are very light in weight and are not bulky for carrying around. Some are not much larger than a pen so they are great for fitting into a pocket, backpack or purse.
There are many occasions when a small monocular can come in really handy – and that’s not just for the uses normally associated with them such as bird watching, plane spotting, hunting and locating golf galls on a golf course. A monocular can also be very useful if you simply want to read street notices or shop and road traffic signage in the distance.
The opportunities for using a monocular are many – when you own a monocular you will amazed how often you use it to get a closer look at things you previously could not see clearly with the naked eye.
If you feel a monocular isn’t suitable for your needs, it may be worth buying a more powerful spotting scope – you can read more about spotting scopes here: What is a spotting scope?
Monocular – an optical viewing device which is very popular with bird watchers, walkers and hunters.