What are the Differences Between Night Vision, Digital, and Thermal?

Humans have been developing ways to make things in life—especially when it comes to survival—easier and faster since the beginning of time. Without some sort of advanced optic that either gathers light or detects and differentiates between temperatures, night hunting and night time military operations would be nearly impossible. Being able to “see” in the dark has made military operations more successful, enforcing the law safer, and many a landowner happy by eliminating over-populated hogs. Advances in digital and thermal imaging have widened the possibilities even more to see targets, game, and other objects that are otherwise invisible to the naked eye. All three technologies use different internal processes to create an image. All have advantages and disadvantages.

Night Vision

Night vision is the ability to see in low-light environments using an image intensification tube (IIT) or a camera sensor (digital night vision.)

Drawing showing the inside of an image intensifier tube
An image intensifier tube is composed of three main parts—a photocathode, a microchannel plate (MCP) and a phosphor screen

An image intensifier tube is composed of three main parts—a photocathode, a microchannel plate (MCP) and a phosphor screen. Image intensifier tubes collect existing light through the objective lens of the night vision unit. This light consists of photons. When photons 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 MCP.  For each electron that enters the MCP, approximately 1,000 are generated.  These electrons are then accelerated and passed towards the phosphor screen. This screen converts the electrons back into photons to create a bright image.  Near-IR spectrum ranges from 750 to 1400nm. 930nm is the limit to what Gen 3 can see into near IR-spectrum. IIT’s cannot be used in daylight conditions without the possibility of damaging the intensifier tube.

Night vision devices are classified in generations, ranging from 0 to 3 and above.

Gen 0

Gen 0 night vision requires active infrared to produce an image. The very first night vision devices, called Gen 0, were introduced during World War II. Both the German and United States military used them. The units worked by projecting an active Infrared Illuminator (IR) light and its imaging was created by an anode/cathode electron accelerator to a phosphorus screen. They were not ideal because they would give away your position to the enemy who also used the same systems. One of the most notable devices were mounted to the German’s Sturmgewehr 44 rifle and called the “Vampir.” The U.S.’s version was nicknamed the “sniperscope,” and used specifically to aid snipers. Both units were bulky and heavy.

Gen 1

Gen 1 night vision uses passive infrared and ambient light and was first introduced during the Vietnam War. Most notable of these was the Starlight. Gen 1 night vision intensifier tubes amplify light about 1,000 times greater than the human eye. Later, Gen 1 night vision devices incorporated an improved photocathode, which increases resolution and reduces distortion. What makes Gen 1 night vision devices less desirable are their blurry edges and lower resolution.

However, Gen 1 night vision devices have gotten incredibly affordable for the average hunter and gun owner. For as low as $120 you would be surprised at the clarity out to 75 yards that Gen 1 night vision gives you.

Gen 2

View through a night vision riflescope showing a coyote in the center of a crosshair reticle.
Night vision is the ability to see in low-light environments using an image intensification tube (IIT) or a camera sensor (digital night vision.)

The Gen 2 night vision scopes and monoculars have much-improved image quality, due to the added micro-channel plate that increases light gain and resolution. However, the Gen 2 night vision devices are just as light sensitive as Gen 1.

Gen 3 and Above

Gen 3 and above use the same technology as Gen 2, but with an added chemical to the tube’s photocathode screen, which increases the tube life up to 10,000 hours and creates the brightest and sharpest image of all generations of night vision devices.The MCP was coated with an ion barrier film to increase tube life. Gallium arsenide is the compound used for the photocathode to increase sensitivity, creating the brightest and sharpest image of all.

Night vision scopes, binoculars, monoculars, and goggles display in green typically and the internal tubes cannot be exposed to daylight or they will burn out. This is the biggest disadvantage of all traditional night division devices that use an intensifier tube.

Night vision devices have come a long way since WWII. In fact, some units are now able to amplify ambient lighting—no matter how dim—up to 50,000 times.

Digital Night Vision

These units do not use an intensifier tube, so it won’t be damaged when used during the day. These devices us a charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS) and a micro display. 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 micro display to be viewed by the user.  Digital night vision devices can be compared to Gen 2 traditional night vision in quality, but are much more effective, due to an infrared illuminator. Some digital night vision devices are also able to record, zoom, and change reticles. This versatility, plus the affordability, makes digital a popular choice for hunters.  

View through a thermal scope with hogs in bright white against a darker forest background.
Thermal imaging uses heat instead of light to create an image. The contrast is extremely helpful in spotting game and targets very quickly during the day or at night.

Thermal

Thermal imaging uses heat instead of light to create an image. Thermal imagers work similar to digital systems, but instead, a microbolometer is used as the sensor array and a special germanium lens focuses infrared light on this sensor. Thermal, like digital, can be used during the day and is also able to record, and zoom. Thermal images detect past 1,000 yards and help you spot targets extremely quickly. The image from a thermal scope or other optic, displays in high-contrast black and white. Thermal imaging technology can detect the smallest of heat difference from 0.01 Centigrade. The technology in thermal optics is so advanced that many units let you see minute details, such as facial features up to 30 meters away. Because no light is needed for thermal to work, targets, game, and other living (warmer) objects are quick and easy to spot even when they are in deep cover, bush, and through fog, smoke and dust.

Because thermal uses heat to work, extreme frigid temperatures can affect how well the optic works.

To read more about how thermal scopes work, click here.

The video below provides a visual comparison of the quality of images produced from each type of device. Notice the low quality of the Gen 1 night vision when compared to the Gen 3. Also, apparent is the difference between the Gen 1, Gen 2, and Gen 3 and the digital and thermal sights. Using black and white provides very clear pictures—crucial when you need to identify a target quickly and accurately at night.

Each have their benefits and setbacks. After learning the differences in the technologies, you are now no longer in the dark how each function and what each can offer you. Ultimately, what it comes down to is what fits your needs the most on which one to choose. All have their place. If it was up to us, we’d have you pick all three!

Click here to shop Pulsar’s night vision, digital, and thermal products.

Night vision or thermal? Which one did you and chose and why? Tell us in the comment section.
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