A monocular is half of a binocular. It is much lighter and more compact than a binocular. Many brands offer at least one monocular as part of their offerings. Prior to the last decade, most monoculars all looked the same (just a straight tube without any style to them) and were mainly 8×21 or 10×25. Currently there are a lot of different cosmetic styles to choose from and a variety of powers and aperture.
The general range of powers is from 5x up to 12x and a few are below or above these powers. There are now models that are zoom monoculars.
Monoculars are very useful for the same applications as binoculars and should be considered for their versatility and portability especially for hiking, hunting, birding, backpacking and other activities where weight is important. Having a monocular in your car, purse, pocket, or backpack allows you to have optics available at a moment’s notice when sudden unexpected opportunities arise. I consider a usable monocular to be in the range of 15 to 42mm for the objective lenses. Smaller than 15mm is just too small to be very useful. Monoculars over 42mm in diameter are considered being a best spotting scope.
Like binoculars, many monoculars are available as waterproof. Monoculars generally have a near focus in the range of 10 to 20 feet (305 to 610cm). But, some units focus as close as one foot (30cm).
There are even specialized units offered to aid golfers in their game. These have a built-in distance scale to determine the distance to the pin. Several monoculars have reticles installed for distance measurements and others have compasses installed for directional information.
Opera glasses (a form of binoculars) are low power, compact optical instruments. These are simple, compact devices utilizing only lenses with no need for erecting prisms. Several decades in the past, full size Galilean binoculars (called field glasses) were quite common for their simplicity. Advances in Porro prism and roof prism optical designs have eliminated the need for full size Galilean types. Opera glasses have a typical magnification range of 2x to 5x. Objective lens sizes range from 12 to 30mm, which is good for concerts, operas, theater, indoor sporting events, or any event where you need some magnification to see the stage, field or other facility where conventional binoculars are too powerful for many situations. Higher magnifications with a wide field of view are not possible with opera glasses. They are rugged, lightweight, and small. They are good for children as they are more durable since they lack a prism assembly that could come out of alignment. However, the optical quality is not as good as most prism type binoculars and they do not have an adjustment to correct for the vision difference between a person’s left and right eye as discussed later in the book. Very few manufacturers offer opera glasses, which is a shame since they are very useful.
Image Stabilized Binoculars Image stabilized binoculars are binoculars which have a means for reducing or eliminating the motion or movement of the view seen when looking through them. The motion or vibration of the image comes from the unsteadiness of our arms and hands or from a moving vehicle. They allow you to see fainter objects and bring out much more detail that you ever thought possible as compared to similar size non-stabilized binoculars unless they were placed on a sturdy tripod. I have used various models from all the manufacturers. The views seen are so enjoyable and they are very comfortable to use. As an example, I have observed a red-tailed hawk nest about 400 yards (366 meters) away while handholding the image stabilized binoculars and watched the young nestlings go through their early life cycle – this would not have been possible with standard binoculars unless mounted on a tripod.
There are passive designs where the stabilization is controlled by gyroscopes. Then there are active designs using sensors. The sensors are part of the binocular, either prisms or lenses, and controlled to correct the binocular shaking or movement. There are also some mechanical designs but the movement continues for such a long time on the ones I tried that they were not satisfactory at all. So, stay with digital types. The steady image is quite enjoyable especially when holding the binocular for any length of time. Bird watchers, hunters, nature observers, astronomers, mariners and people viewing distant scenery can all benefit from using these. A few companies (Nikon, Zeiss, Fujinon, and Canon to name a few) are offering these binoculars and they are expensive but the benefits may outweigh the cost and heavy weight.
Night Vision Monoculars and Binoculars
Night vision optics have the ability to see in low light conditions and in total darkness. There are mainly two types of these binoculars: Intensity range – image enhancement is by using an image intensifier tube or other means. The image is a green color and they have been around for many years but are not a large factor any longer. They detect small amounts of visible light (even from stars) and amplify it so we can see an image. Newer digital technology has a built-in infrared illuminator to allow usage in ambient light or in total darkness. The images are clearer, brighter and sharper. Spectral range – thermal images from the enhanced spectral range obtained using near infrared or ultraviolet radiation. When first introduced only black and white images were possible. During the last decade, digital color models became available. This type of technology does not detect any light but it does collect the infrared radiation from bodies (human or animal) and other warm objects to form an image.
There are many uses for night vision binoculars – pilots, farmers, boaters, hikers, hunters, astronomers, military, and law enforcement to name a few. A few of the popular brands are ATN, Bushnell, Carson Optical, Newcon, Pulsar, Sightmark, and Yukon.
GPS binoculars have been around for a number of years but not very many of them are available. They are very useful for giving you GPS coordinates. Newer versions have a built-in LCD along with a digital compass to be able to see the information easily. Some models give the user elevation and other information.
Binocular Rangefinders Binocular rangefinders are compact and handy electronic devices to use for determining distances up to 1000 yards (meters) and more on some models. The common rangefinders available are laser rangefinders from Bushnell, Leica, Swarovski, and Zeiss. Rangefinders make distances easier to determine by hunters, mariners and hikers. The military and law enforcement and other agencies have many uses for these products.
Digital binoculars are a combination binocular and built-in digital camera. You can take snapshot images or video and the captured image is the same magnification seen in the binocular on many models. There are many different features depending on the brand and model. Many have optical zoom as well as a digital zoom to increase the power but the digital zoom results may not be so good. Digital binoculars were a big fad during the 2000s with many different brands and many models available but today they have virtually disappeared from the market due to their low resolution, smart phones with cameras and point and shoot cameras with increasing resolution and lower costs. Bushnell and Barska are two of the main suppliers now.