How exactly do night vision binoculars work?

We explore how specialist night vision binoculars enable us to see in the dark, and what you should look for when buying a pair

man using Nightfox Swift Night vision goggles
(Image credit: Nightfox )

Nature never sleeps, but when the light dims, so does the usefulness of a pair of binoculars – even ones with the largest of objective lenses. If you want to be able to embark on some nocturnal nature spotting, you'll need to invest in a pair of the best night vision binoculars or goggles

Yes, there are specialist tools we can buy to enable us to see further in the dark – particularly useful if we want to observe wildlife that only typically comes out at night, or use the binos for security or surveillance purposes. In this article, we take a closer look at what night vision binoculars are, and, should these sound perfect for your requirements, what you should look for when buying.

How do night vision binoculars work?

While most of today's best binoculars are geared towards daytime use, both night vision binoculars and night vision goggles – the latter of which we strap to our heads – are set up specifically to help you observe things at night. The two are pretty similar in approach, in that they use image enhancement and light amplification technology to allow us to observe in the absence of daylight. Available ambient light is gathered by the device and intensified to present us with a clear, green-hued recreation of the scene in front of us.

Why do night vision goggles show in green?

It has been determined that a monochromatic night vision image is easiest distinguished by human eyes when that image is green, as our eyes are more sensitive to that colour and it's less tiring to look at for longer periods.

Night vision goggles vs binoculars: which are better?

With goggles comes the obvious advantage of being ‘hands free' in the dark and being able to view in multiple directions, even if resembling an extra from a sci-fi film or Orbital's 1994 Glastonbury set when doing so. With night vision binoculars we also have the possibility of tracking subjects in the dark. That said, like with any pair of binoculars, we need to pay attention to the size and weight of the unit, especially if we're going to be heading into the great outdoors and using it for prolonged periods of time. Another alternative in this case is the more compact and typically lighter night vision monocular, which works and operates in a similar fashion, but as the name suggests with the use of just the one eye.

What features should I look for in a pair of night vision binoculars?

For starters, price, like anything else, will vary dependent on the number of features, the degree of specification involved plus the wear and tear our night vision binoculars are expected to stand up to. If we're considering outdoor use, then to prevent fogging some form of waterproofed or moisture and dust repellent construction can come in mightily useful, as can a ruggedized or rubber exterior to aid grip and prevent slips and fumbles in the dark.

Solomark Night Vision Binoculars

Solomark Night Vision Binoculars 

(Image credit: Solomark)

Chiefly though, as with any pair of binoculars, a sufficient wide-angle view and range, coupled with a large and bright lens, will be key, as will, for those of us who wish to continue observing and tracking quarry in not just low light conditions but also complete darkness, a built in IR or Infrared illuminator with perhaps some form of user adjustment offered. For larger binoculars we might also want to examine whether a tripod mount is included – especially if we're going to be fairly static ourselves in terms of movement. Added to this, large buttons and obvious controls are an asset, particularly in the dim light, as is a comfortable fit in terms of eye relief. 

Be aware too that night vision binoculars and goggles require power, so check whether this is a readily accessible and replaceable type, such as AAs or AAAs. It's hard to find a charging point in the middle of the woods, after all. Some clever night vision binos will also deploy an automatic shut-off feature if they're exposed to bright light, thus usefully prolonging battery life. And others allow us to take images and videos, stored on SD memory card, should that be a tempting possibility.

If portability and travelling light is key, as noted we might also want to examine what's available in terms of night vision monoculars too. Yes, they might not offer as wide a field of view as binoculars, but can prove useful in a tight spot and when space in our kit bag is an issue.

Gavin Stoker
Gavin Stoker

Gavin Stoker has been writing about photography and technology for the past 20 years. He currently edits the trade magazine British Photographic Industry News - BPI News for short - which is a member of TIPA, the international Technical Imaging Press Association.