Night Vision Buying Guide

Night Vision buying tips

Night vision devices allow you to see in very low lights. Like binoculars or a monocular, night vision devices can also magnify objects so they will appear closer, but the main use of night vision is to see things that your eye wouldn't normally be able to see in the dark or in low light. Many hobbies, and even some jobs, require night vision. You may want to use night vision for the following activities:

• Observing nocturnal wildlife
• Some sports, such as night hunting or fishing
• Boating in foggy weather or at night
• Professional security or neighborhood watch programs
• Camping
• Nighttime driving
• Ghost hunting and paranormal research
• Search and rescue

The type of night vision device you choose will be affected by the activities you plan on using them for.

Types of night vision devices

The term night vision usually refers to a whole device that allows you to see better in low light; however, night vision devices do this in different ways and to different degrees. There a several types of night vision devices.

• Night vision goggles give you a hands-free option for low-light vision, often without magnification. Night vision goggles are perfect for exploring the woods at night.
• Night vision binoculars will magnify the view with realistic depth perception, making them perfect for navigation on land or sea. You can also use night vision binoculars for security.

• Night vision monoculars are lightweight and can fit conveniently in a pocket. Use a night vision monocular when you only need to check things out for a few minutes at a time, such as for security.
• Night vision cameras let you take pictures of what you see, and night vision video recorders let you film the action in the dark.
• Night vision glasses can be used while driving at night or in foggy weather because they don't magnify at all. They also help reduce the glare from oncoming headlights.

Methods of night vision

Night vision devices have two methods of creating images in low light.

• Light amplification: When there is only a bit of starlight or moonlight, night vision devices take that small amount and enhance it enough to allow you to see better. It even uses light at the low end of the light spectrum that is not noticeable to the naked eye. This is either done passively, by filtering colors and relying totally on ambient light, or actively, with an infrared light source within the device.
• Thermal imaging: The heat given off by objects, animals and people appears as light at the upper end of the infrared light spectrum, which is not visible to the naked eye. Thermal imaging night vision detects this heat and creates an image with it. The image created by these night vision devices is called a thermogram.

Night vision generations

As improvements are made in night vision technology, night vision devices have been able to provide better vision with less light. The advancements in night vision devices over time are noted in the description by the generation number.

• First generation: Using technology from the 1960s, first generation night vision devices are still in wide use today because they are the least expensive. Most first generation night vision devices need the equivalent light of a full moon in order to function. These supply enough night vision for the typical hobbyist.
• Second generation: With technology dating back to the 1970s, second generation night vision devices require less light to make an image brighter. These can be much more expensive than first generation night vision devices, but the image produced is noticeably better.
• Third generation: Starting in the 1990s, night vision devices have been made with gallium arsenide inside the light amplification tube. This technology is very expensive, but the image is significantly clearer and brighter than second generation night vision devices. This is the level of technology used by the military.

Many optics devices have the ability to produce images in low light, but if there is no generation information, then it is not a true night vision device.

Night Vision care

Some night vision devices require the use of batteries, so be sure to read the product description for the one you choose. In general, you can care for your night vision devices by never dropping them and by storing them in a safe pouch that won't scratch any lenses.

One more important concern in taking care of your night vision devices is to be aware of any local, national or international laws restricting the use or ownership of such devices. Particularly if you plan on traveling internationally with your night vision devices, you'll need to be aware of any export laws.

Night Vision terminology

There's quite a bit of science that explains night vision, but only a few terms will be important as you choose a night vision device.

• Diopter: a measurement referring to the way optics are focused.
• Exit pupil: the measurement, in millimeters, of light that comes out through the eyepiece. Most night vision devices will have a large exit pupil, at least 7mm, to let as much light into the user's eye as possible.
• Eye relief: a measurement in millimeters of the distance between the eyepiece and the eye; this is particularly important to eyeglass wearers, who need a longer eye relief to see the full field of view; and shooters, who need a longer eye relief on weapon-mounted night vision in case of kickback.
• Gain: the number of times a night vision device amplifies light.
• Line pairs: a measurement of image resolution; the more line pairs, the sharper the resolution.
• Objective lens: the lens (or lenses) closer to the object being looked at; the larger the objective lens, the more light that is let in.
• Photosensitivity: a measurement of the ability of a night vision device to amplify light.
• Tube blemishes: small spots common to all night vision devices; a night vision device with small or few blemishes will demand a higher price.

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