Answers:

What do the numbers mean?

Binoculars are normally identified by two numbers such as 7x35 or 10x50. The first number is the magnification value and the second one is the diameter of the objective lens in millimeters. For example, 7x35 means this binocular magnifies objects 7 times and the objective lens is 35 mm.

Magnification

Magnification makes an object look several times bigger than when seen with the unaided eye. 7x means an object 70 meters away appears as though it is only 10 meters away.

Objective Lens Diameter

Objective Lens Diameter is important because many of the performance characteristics of a binocular are determined by the diameter of this lens. The larger the diameter, the more light will reach your eye thus providing a brighter and sharper image. However, the larger the diameter, the havier and bulkier the binocular will be. It is measured in millimeters.

Field of View

Field of View is a term which describes how large an area can be viewed. This is expressed in degrees of angle or the number of meters per 1000 meters of distance. Normally the higher the magnification is the narrower the field of view. On some binoculars a special design of lens provides a wider field of view than normal. These binoculars are called wide angle binoculars and are designated WA.

Resolution

Resolution describes how sharp or clear an object appears. Resolution is primarily determined by the quality of an optical scheme, quality of optical parts and the device on the whole. Resolution is measured in angle seconds or in lines per mm.

How does Night Vision work?

Night Vision Devices are electronic optical devices which collect and amplify existing light through the objective lens which is then focused on the image intensifier. These devices are very sensitive to the wide spectrum of light - from visible to infrared. Auxiliary illuminator can increase existing light in infrared spectrum by directing light beam invisible to man's eyes. You do not see “through” a device. You see the amplified electronic image on the screen with luminophore coating. Therefore the image is in green colours. Inside the intensifier, a photocathode is "excited" by the light and converts the photon energy in to electrons. These electrons are accelerated across an electrostatic field inside the intensifier and strike a luminophore screen (like in a TV set), which emits an image that you can see. It is the acceleration of electrons, which provides gain and enhances the image. The eyepiece amplifies the image. Image converter (a tube) is a main part of a night vision device. It directs and accelerates photoelectronic stream. Basically the quality of NV devices depends on characteristics of a tube and quality of optical parts. According to practice accepted in the world tubes are classified as follows: Generation I, II, III (with some intermediate variants Gen. I+, II+).

Image Tube Genaration

Generation: Gen is a commonly used abbreviation that refers to the power or “generation” of image intensifier night vision tubes. The key difference between the night vision generations is the intensifier technology. The tubes of 1st, 2nd and 3rd Generations are generally recognized, but the US government has recently begun purchasing newly issued tubes, recognized as Gen 4 by certain companies. 1st Generation: 1st Generation or Gen 1 is currently the most popular commercial grade of night vision tube in the world due to their relatively low cost. Gen 1 devices amplify existing light several hundred times. With many Gen 1 units, it is normal to hear a slight high-pitched whine when the unit is on. This whine not only proves distracting to many users, but also limits stealth in various tactical applications. Yukon technicians have corrected this drawback to ensure that all Yukon Gen 1 devices are silent and allow for undetected use. Gen 1 tubes frequently produce an image that is slightly blurry around the edges. This phenomenon is known as “geometric distortion.” When you turn a Gen 1 tube off, it may glow green for a short time. For this reason, an on/off light indicator is especially advantageous and prevents the unit from being left on accidentally resulting in decreased tube life. 2nd Generation: 2nd Generation or Gen 2 is primarily used by law enforcement or for professional applications. The primary difference between Gen 1 and Gen 2 is the addition of a micro-channel plate (MCP). The MCP is located directly behind the photocathode, where it amplifies electrons, resulting in a brighter and thus sharper image. For this reason, a Gen 2 unit frequently costs between $500.00 and $1000.00 more then a Gen 1 device. 2+ Generation: Gen 2+ intensifier tubes are produced with similar technology to that of regular Gen 2 tubes, but the resolution quality is improved. Gen 2+ devices are a good choice for individuals who want premium grade optics without Gen 3 prices. 3rd Generation: Gen 3 is the most powerful, recognized night vision tube available. Gallium Arsenide is added to the photocathode, resulting in a brighter, high resolution image. Due to their premium status, many Gen 3 units will cost in excess of $3000.00. 4th Generation: The US Government is currently purchasing tubes that are identified as 4th Generation. Since the terminology is relatively new, some industry professionals consider Gen 4 as merely an improvement upon Gen 3.

Exit Pupil

The diameter, in millimeters, of the beam of light that leaves the eyepiece is the "exit pupil.” Image brightness directly correlates with the exit pupil; the larger the exit pupil, the brighter an image. Having a large exit pupil is especially advantageous under low light conditions and at night.

Eye Relief

As the name implies, eye relief refers to the distance, in millimeters, that an optical device can be held from the eye and the full field of view can still be comfortably observed. Individuals with glasses benefit in particular from longer eye relief with all optical devices. Considerable eye relief is also imperative when using riflescopes due to recoil. Without it, a sportsman risks serious eye trauma.

Lens Coatings

The optical elements of the binocular are coated to reduce internal light loss and glare, which in turn ensures even light transmission. The result is greater image sharpness and contrast. The term "multi-coated" refers to high-grade lens coatings, which reduce internal light loss and glare. The result is even light transmission, greater image sharpness, and better contrast. Multi-coated and fully multi-coated lenses are premium and give the best light transmission and brightest images. Multi-coated or fully multi-coated lenses offer the highest quality of imaging.The term “fully multi-coated” refers to premium lens coatings, which reduce internal light loss and glare. The result is even light transmission, greater image sharpness and better contrast. Fully multi-coated lenses are premium and give the best light transmission and brightest images. It provides the highest quality of imaging.

Night Vision

Night Vision technology consists of two major types: image intensification (light amplification) and thermal imaging (infrared). Most consumer night vision products are light amplifying devices. All Yukon Night Vision products use image intensification technology. This technology takes the small amount of light, such as moonlight or starlight, that is in the surrounding area, and converts the light energy (scientists call it photons), into electrical energy (electrons). These electrons pass through a thin disk that's about the size of a quarter and contains over 10 million channels. As the electrons travel through and strike the walls of the channels, thousands more electrons are released. These multiplied electrons then bounce off of a phosphor screen, which converts the electrons back into photons and let you see an impressive nighttime view even when it's dark.