How Does Traditional & Digital Night Vision Work!

night vision goggles

Without a doubt, night vision revolutionized warfare. It gave forces with this amazing technology an unparalleled advantage when the sun went down. To this day, it gives American forces overseas the ability to own the night.  

Night vision has humble beginnings. When it was first created, it required a battery so big it needed a backpack. As technology tends to do, the devices got smaller, clearer and more efficient. These days, night vision is teeny tiny and more useful than ever before!  

If we asked most people how night vision works, we would probably hear the word “magic”. Our natural curiosity got the best of us, and we wanted to find out the truth behind the magic. We figured we could let you folks come along for the ride!  

 

The Science Behind Night Vision 

Night vision’s end goal is to give the user a clear and consistent picture while using the device. To do this, modern night vision doesn’t create light but instead amplifies existing light. It accomplishes this through a series of simple steps.

 

how night vision works  

The first thing that has to happen is some form of light has to enter through the front lens of the device. This light can come from anywhere, including the moon or stars. As the light reflects off of everything else, it creates even more light. Reflection is a must-have for night vision.   

To understand light, you have to understand that light is made of photons. These photons enter the device through the front lens and reach something called the photocathode. The photocathode then takes those photons and converts them into electrons.  

Solar panels do the same thing, but photocathodes are a little more precise. The electrons then meet something called a photomultiplier. This is a type of photoelectric cell. Here the electrons are multiplied over and over again to create tons of electrons.   

Now a handful of electrons are a bucketful of electrons! The night vision device takes those electrons and throws them into a phosphor screen, and the crash creates tiny flashes of light. If it were just one electron the flash of light wouldn’t even be visible! 

The end result is a much brighter and clearer picture of whatever the device is looking at. This is an easy explanation of how night vision works. What’s amazing is that all of this happens instantly. Simply turn it on, and bam! The world is glowing green around you.  

 

Digital Night Vision

Digital night vision is a much cheaper option for night vision use, often cheaper than Gen 1 devices. It doesn’t amplify light via intensifier; instead, it works through a digital signal.

Digital night vision processes and converts the image you are looking at to an electric signal. This signal is sent through a charged coupled device image sensor. These image sensors are pretty standard in digital video cameras with night vision modes.

This image sensor then sends the signal to a screen. This screen presents you the picture you are looking at. So when you look through a digital NVD, you are looking at a screen, not directly at the image.

Digital night vision is simpler and more affordable. The camera industry made this possible. However, it is quite limited in range and resolution compared to Gen 2 or Gen 3 standard night vision.

 

Wait, Why is It Green?

Interestingly enough, the photons carrying the light to your system carry every color of light. However, all we see through the tube is a greenish glow. Sometimes grey with digital, but that’s another article.

When the photons are converted to electrons, they have no way of carrying their colorful light. Instead, the color is turned to black and white. That still doesn’t answer our question though. Why is the picture green?   

That greenish glow is part of the culture surrounding night vision. The glow and the odd hum. Spoiler alert for life, there is no hum but the green glow is very real! In fact, we see the greenish glow on purpose.  

The phosphors applied to the screens purposefully turn light into that greenish glow. The color green was chosen because the human eye picks it up the fastest. Our eyes are also more sensitive to green, so it is less harsh and more comfortable over extended periods of time. 

We have used lots of different types of night optics, including thermals. The colors of thermals are often black and white, and after a short period of time they become uncomfortable to look at. We have never felt that same discomfort when using proper night vision.  

 

What About Thermals? 

thermal imageTechnically the term night vision could apply to thermal optics, but due to the standardized lexicon thermals are left out. You can certainly see at night with thermals, but they are fundamentally different than night vision.  

Night vision works off the light that objects reflect. Thermal vision works off the heat that objects give off. Thermal imaging can detect the heat generated from people, engines, light bulbs, and much more. Night vision will only show those things if there is some light. 

Thermal imaging is great for detecting prey. We would say it’s even faster than night vision at finding living things. Since they can’t stop giving off heat, they will stand out regardless of their natural camouflage. Not so with night vision. 

Thermals vary in terms of how they work and the image they provided to the user. It could be black and white, green, or even rainbow (made famous by movies like Predator). These brighter colors allow living things to stand out against a drab background.  

Unfortunately, if something doesn’t give off heat it is difficult to see. Thermals do not show the little details that night vision provides, such as terrain. With thermals, a river doesn’t look like anything. With night vision, a river looks like a river.  

See our full comparison article on night vision and thermals.

 

What if there is No Light? 

infrared illuminatorWe know that night vision requires light to function, right? Moonlight, starlight, and ambient manmade light all keep your NVGs functioning. Rarely will you ever find yourself in a situation with zero light, right?  

Well, maybe or maybe not. If you are indoors, you may come into a room without windows. Maybe the curtains are blocking any external light from entering. What happens now? Not much! Night vision won’t do you any good in this situation. 

What you need for times like these is an infrared illuminator. An infrared light acts like a flashlight that can only be seen while wearing night vision. Unfortunately, IR does have limited range. Also, it can reflect off of dust and smoke, limiting its range even more.  

Try using your night vision on a night where there is barely any external light. When the moon is nowhere to be seen and the clouds are heavy. You will notice how little you can see even in those situations. That’s why infrared illuminators are a must have when using night vision.  

 

Go Green! 

night vision view of hogEveryone from hunters to animal lovers use night vision, and it is important to understand how it works to truly appreciate the device. Night vision is an amazing piece of technology!  Although developed for military use, it has emerged into civilian life and become extremely popular. 

The market for night vision is growing daily, and these optics are becoming more affordable and more available each passing year. Now that you have a basic understanding of night vision, you can approach your purchase with some insider information.  

Make sure to also check our buying guides for night vision goggles, monoculars and binoculars!

 

How Does Traditional & Digital Night Vision Work!
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Travis Pike
Travis Pike is a former Marine Machine gunner who served with 2nd Bn 2nd Marines for 5 years. He deployed in 2009 to Afghanistan and again in 2011 with the 22nd MEU(SOC) during a record setting 11 months at sea. He’s trained with the Romanian Army, the Spanish Marines, the Emirate Marines and the Afghan National Army. He serves as an NRA certified pistol instructor and teaches concealed carry classes

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