Everything you need to know about buying a night vision device.
Night vision technology revolutionized warfare, surveillance, law enforcement and military operations, as well as night time hunting. Night vision optics like night vision goggles, binoculars, riflescopes and monoculars provide a way for us to see and positively identify objects and targets in the dark.
Due to their affordability, the most popular night vision device is a monocular. The best night vision monoculars under $200 are:
- Firefield 5x50mm Nightfall
- ATN Night Trek 3x
- Sightmark Ghost Hunter 2x24mm
- Stealth Cam
- Night Owl Xgen 2.1x
- Carson AuraPlus 2x
- Bushnell Equinox Z
How Does Night Vision Work?
Traditional or tube-based night vision systems use an image intensifier tube (IIT.) An image intensifier tube is composed of three main parts—a photocathode, a microchannel plate (MCP) and a phosphor screen. IIT’s collect existing ambient light through the objective lens of the night vision device. This light may be starlight, moonlight or artificial light (streetlights or through a built-in infrared illuminator.)
When photons (light) pass through the photocathode, they are converted into electrons. Once through the photocathode, the electrons are then released into a vacuum and accelerated towards the microchannel plate.
The microchannel plate is a thick glass disc with millions of small channels. When the electrons strike the inner walls of the channels, a chain reaction begins generating secondary electrons. For each electron that enters the microchannel plate, approximately 1,000 more electrons are generated.
These electrons are then accelerated and passed towards the phosphor screen. This screen, located on the output window of the intensifier tube, is a thin light-emitting layer which converts the electrons back into photons to create a bright image.
Night Vision Generations
There are four generations of night vision—each generation and variance generally improve upon the previous.
Gen 0 requires active infrared to produce an image.
Gen 1 uses ambient light to produce an image and is dependent on active infrared yet has an improved photocathode for increased resolution and distortion reduction.
Gen 2 incorporates a microchannel plate to increase gain and resolution and inverted optics to decrease the size of the tube.
Gen 3 has an ion barrier coating on the microchannel plate that increases tube life, Gallium arsenide photocathode increasing resolution and increased light amplification.
The functional differences between Gen 1 and Gen 2 are minimal, however, Gen 2 has 45 times more light amplification and 20% better resolution. If the price justifies itself to you, then Gen 2 is worth the investment.
Night vision devices that use an image intensifier tube cannot be used in daylight without risk of permanently damaging them.
Digital Night Vision
Digital night vision devices do not use an image intensifier tube. They use a charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS) sensor and a microdisplay. Light that is projected onto the CCD or CMOS array from the objective lens is converted to an electronic signal. This signal is then processed and sent to the microdisplay to be viewed by the user. The image is usually in black and white, but digital night vision displays can be in any color. CCD and CMOS sensors are more sensitive than image intensifier tubes and can see high-frequency infrared light this is not visible to the human eye.
Digital night vision devices can be used during the day safely and have become a viable replacement for Gen 2 night vision due to the same quality of resolution and clarity but are generally more affordable then Gen 2 devices.
Both generational and digital night vision can utilize a built-in infrared illuminator that acts as artificial ambient light allowing users to see in total darkness.
Resolution is the ability of the image intensifier tube to distinguish lines and detail clarity. The USAF 1951 Resolution chart is the standard method for testing resolution for night vision optics. Resolution for tube-based night vision systems is specified in lines per millimeters (lp/mm). Generally, Gen 1 tubes range from 30 to 36lp/mm, Gen 2 from 45 to 54 lp/mm and Gen 3 from 57 to 72 lp/mm.
Why is Night Vision Green?
NIght vision is green because our eyes like looking at green for longer than they do black and white. We’re more sensitive to green light. Simply put, green is just easier for us to look at. It also helps produce a more accurate image and conserve battery life.
Why Should I Buy a Night Vision Device?
People buy and use night vision not necessarily to magnify images that are far away but to identify objects and targets in the dark. Night vision will help you recognize facial features and distinguish between animals. Its most powerful benefit is positive identification of a target or subject in low-light environments. On a Gen 1 night vision device with standard 2x to 4x magnification, identification works well from 30-100 yards (depending on availability of ambient light,) with larger objects such as buildings being identified even further away. Night vision allows you to observe wildlife or game without being detected.
Which Night Vision Should I Buy?
Night vision can be extremely expensive, ranging in the tens of thousands of dollars for high-end night vision goggles and scopes. Night vision monoculars, however, due to their smaller size, are more affordable and therefore the most popular of night vision devices for consumers.
What are Monoculars and How do They Work?
Monoculars share many similarities with spotting scopes and telescopes, as all three magnify an image, have one eyepiece and you use them viewing with only one eye, however; monoculars are made much smaller with lower magnifications. Monoculars are made to be compact, lightweight and very portable.
Monoculars, like all magnifying devices, are measured in magnification or power and lens size. You will see it displayed with two numbers—the first number is the unit’s magnification and the second is the lens size. The magnification of the monocular makes the object you are viewing that many more times larger than you would see it with your naked eye.
Magnification is the process of enlarging the appearance of an object using magnifying lenses. Magnification, in turn, affects resolution, light transmission, and the field of view. In general, the lower the power, the wider the field of view, but a slightly lower system resolution. The higher the power, the narrower the field of view, but a higher system resolution. Magnifications over 5x suffer a significant reduction in light transmission. Images with higher than 5x power will appear much darker to similar devices using a lower magnification. To compensate, the objective lens diameter must be increased, but total weight and cost of the unit also increase.
2x and 4x are standard and the most popular magnifications for a monocular. These ranges allow you to steadily view an object or target clearly from 30 to 100 yards while maintaining a significant field of view.
As the magnification of the monocular increases, the field of view decreases. The field of view is how much of the object you see. For example, the field of view is listed usually in feet at a certain distance usually in yards. If the field of view is 250’ at 1,000 yards, you will see 250 feet of the object or target when you are 1,000 yards away.
Measured in millimeters, the second part of the monoculars’ specification is the lens size. The larger the lens, the wider field of view and the brighter the image. However, bigger lenses add bulk and weight to the unit.
Monoculars, especially night vision monoculars, are very versatile. Usually handheld, you can also mount monoculars to a headpiece or your rifle. You can use your monoculars for a variety of reasons—surveillance and security, camping and hiking, stargazing, wildlife observation, hunting, fishing or just for fun!
The following seven night vision monoculars are the best for the money.
When considering purchasing night vision, you must realize that the saying, “you get what you pay for” is truly correct. The technology in night vision optics isn’t cheap and you aren’t going to find military-grade night vision without dropping literally thousands of dollars. However, because optical advances in manufacturing companies can make affordable night vision that works successfully for night hunting as well as regular recreational uses.