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What Is The Difference Between Night Vision and Thermal Scopes?

Night vision and thermal scope

Some animals are naturally born with the ability to see in the dark. Unfortunately, humans are not one of them. We were left to stumble around until someone finally figured out a way to see in the dark around the year 1800. 

As time went on the methods were refined. As of today, there two main methods used: thermal or night vision. In this article an explanation of how each scope works; the pros, and cons of each type; and finally, a guide to help choose which one is the right fit for you.

Thermal scope

To understand Infrared Scopes, you first need to understand the electromagnetic spectrum. This spectrum includes everything from radio waves, to visible light, and beyond. The human eye can only see a small fraction of these wavelengths. This is known as the visible light spectrum, and it makes up everything you can see right now.

Just beyond the range of human vision lies the infrared spectrum. For this article heat and infrared will be equivalent. The infrared spectrum was first discovered in 1800, and the first infrared sight was invented in 1901, and it could see a cow in complete darkness at 400meters or about 450yards.

Thermal scopes take heat energy and translate it into colors that humans can see. A lens in the scope collects the infrared light in “view” of the scope. This infrared light is then scanned by sensors that send a signal to a microprocessor.

The microprocessor translates different amounts of heat into different colors the human eye can see. A thermal scope is a camera that takes pictures of infrared light and then translates it into visible light. This whole process takes only a few fractions of a second. 

A thermal scope completes this process about 30 times a second giving the user a live look at what is in front of him. As thermal optics developed overtime they split into two main categories; cooled, and uncooled.

Thermal scopes are un-cooled meaning they operate at room temperature. These scopes allow users to see a basic image within a temperature range of -4f to 4,000f with a sensitivity of about .5f, more than enough for the average person.

A cooled thermal imager is usually cooled with a system of liquid nitrogen. This makes them bulky and fragile and not very practical to put on top of a hunting rifle. Cooled thermal imagers are often used on military observation planes or even satellites.

A thermal imager cooled by liquid nitrogen is much more sensitive to heat than an uncooled one.  A cooled thermal imager is sensitive to changes of temperature up to .02f.  This allows the user to see an unbelievably clear image from extremely far away. However, with the way technology is progressing it may be possible to one day produce a handheld cooled thermal optic.

Pros

  • Works in Zero light Condition
  • Works during the day
  • Sees “Through” camouflage
  • Can see residual heat such as droppings, blood or a dropped gun
  • Allows the user to see through leaves, twigs, or other thin items
  • Can see through smoke, dust, fog

Cons

  • A bit more expensive
  • Not very durable
  • Heavy and bulky
  • Doesn’t provide enough detail for positive threat identification
  • Requires regular maintenance
  • Images require interpretation
Night Vision Scope

Unlike thermal scopes which produce images from heat, night vision scopes enhance the already existing light making it visible to the humane eye.  Dim light enters the lens of a scope which strikes a photocathode.

The photocathode converts the light to electrons. The electrons then pass through an amplifier that adds electrons which strengthens the signal. These electrons collide with a photo screen and create tiny flashes of light. These little flashes of light are what a user sees when looking through a night vision scope.  

A night vision scope works like a speaker. It takes an electrical signal and then amplifies the signal to make it recognizable to humans.  Unfortunately, this method doesn’t produce colors but rather intensifies the difference between the light levels.

The light enhancing night vision is what is usually imagined and portrayed in Hollywood when people think of night vision. Different shades of green with brighter green representing more intense light and darker green or black were no light can be found by the sensor.

Pros

  • Cheaper than thermal sights
  • More Durable
  • Instant startup
  • Provides a more detailed image
  • Longer battery life
  • Images are more naturally interpreted
  • Works fine in the rain

Cons

  • Doesn’t work in Zero light Condition
  • Can’t see through dense smoke or dust
  • Bright lights render it ineffective
  • Most models don’t work during the day (some modern models do)
  • Requires image contrast
night vision and thermal scope compare

Picking the Right Scope For you

Thermal and night vision scopes have their advantages and disadvantages. This makes it difficult to determine which one to buy. There are several factors one needs to consider: the environment the scope will be used in, the price range, and the light levels the scope will be used in. It is important to consider the use of the scope as well. Using the scope for hunting, home defense, tactical use, or maybe observation such as trail cams will impact the type of scope that matches your needs.

Hunting

Hunting

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If you are considering buying a thermal or night vision scope for hunting look no further. This is an extensive run through of the advantages and disadvantages of using thermal or night vision scopes to hunt.  Although using a night vision scope requires some ambient light to work. The stars and moon will produce enough light for the scope.

One should try to avoid hunting on a new moon with a night vision scope as the ambient light will be significantly less on a night with no moon.  A night vision scope will produce a clearer and more recognizable image to an untrained eye, rather than the blobs of different color produced by thermal imagining.

A night vision scope will be much easier for a hunter to pick up and hit the trail with than a thermal sight which will require some training to use properly.  If you are hunting an animal where quick recognition is essential, then night visions scope has the advantage. However, if you are hunting from a blind or have a bit more time to analyze the image then a thermal scope will work great as well.

Observation

To get the dream deer or to secure your property thermal and night vision cameras are a sure-fire way to get the job done. Trail cams are a great way to quickly find out which of your hunting spots you should be spending time hunting at. While thermal and night vision cameras can help you sleep a bit better at night.

Thermal Cameras provide a great way to observe animals or monitor property while remaining undetected. Since thermal cameras analyze the infrared spectrum humans and most animals can’t see the images being taken.

This is important when filming gaming as a bright glow or flash used by some cameras can spook game, and possibly cause game to leave the area. This would leave you with nothing but a beautiful picture of the one that got away. Not only can you find what areas the animals are living in, but Thermal cameras help track the animals as well.

Thermal cameras can see heat trails left behind by animals. Some are sensitive enough they can report where an animal walked. Most thermals cameras will easily be able to follow a fresh blood trail to help you find your kill.

Night vision cameras are much cheaper than thermal ones.  Although, they tend to have anywhere from a low to high glow that animals and humans can observe. The amount of glow given off by a night vision camera is usually inversely related to the price of the camera. The more expensive the camera the less light it will give off.

Using night vision as a security camera will provide a better image with more identifiable features of the potential crook. Night vision cameras will let the intruder know he is being filmed as well. The simple act of letting crooks know they are being recorded can prevent crime. A combination of night vision and hidden thermal cameras will provide the best security.

Home Defense

Home defense

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There are several factors that favor night vision for use in home defense. The first factor is startup time. While night vision scopes start up almost instantly when the bottom is pressed. Thermal Scopes have a delayed startup time.  In the instance of home defense, time is critical and one might not have the extra time to sit around and wait for the scope to warm up.

The second factor for home defense is threat identification. Night vision produces a clear image where the user can see basic features that might help him identify who is at the other end of the barrel. Thermal scopes don't provide this clear picture, showing just the difference in heat. It is impossible for the user to be positive who he is looking at through the scope.

The third factor is a bit less concrete. The house must be light enough for night vision to pick up.  Thermal scopes have the advantage here as they will work in just about any lighting condition. One also needs to be aware that if the intruder shines a bright light from close range at a cheaper night vision scope will be disabled.

With a thermal scope, the user will not be affected by the changing in the light condition since thermal scopes don't depend on light but rather heat.

Night vision scopes are still preferred for use in home invasion due to the overwhelming ability of threat identification. This ability alone makes night vision the best of the two options because with home defense mistaking a bystander for a target is unacceptable.

Tactical use

For tactical use, the choice between night vision and thermal can get very complicated as there are a lot of factors that change constantly.  To address these factors in multiple different situations, and to help users make the appropriate choices for the above categories. Each factor such as environment, price, and interpreting the scope specifications is addressed below.

Environment

The environment the scope will operate in plays a big role in determining which scope is the preferred option.  Dense foliage such as trees and brush are common in many hunting and tactical environments.

Since night vision scopes work by amplifying the already present light.
the scope cannot distinguish between thick leaves and an animal standing behind thick leaves.  A user well trained with a thermal scope can easily distinguish the difference between n the leaves and an animal. The ability of the thermal scope to read infrared helps a user to see through objects that would normally hinder the user’s sight. 

If you are a hunter then durability isn’t as essential the deer might get away, but life goes on. However, if you are using the scope for tactical reasons whether it be a soldier or police durability is essential as failure could cause loss of life. 

Night vision scopes tend to roll with the punches a bit more than thermal scopes.  Night vision scopes have fewer open ports and moving parts than thermal scopes so if sand, water, and dirt are a big problem then probably best to go with the night vision scope. 

Weather can do some weird things to both the thermal and night vision scopes. The different methods of amplifying light vs reading infrared will cause different scopes to react a bit differently in the same weather situations.

Night Vision scopes won't work in dense fog, smoke, sand, or dirt. If operating in a location where these weather phenomena are common. One needs to be extremely wary. Fog, dust, or smoke at night will block so much light that night vision scopes cannot pick out any difference between light intensities.

This can cause the night vision scope to be completely green or black, which is not much help to whoever is using it. One also needs to be careful about streetlights, spotlights or flashlights when using night vision.  Any of these artificial lights will flood the night vision goggles and render them useless if the light is too bright.

Although not important while hunting the presence of artificial light is a present and impactful factor when using the scope for military, police, or home defense purposes

Thermal scopes can be impacted by the weather too. Thermal scopes aren’t affected by fog or smoke, but they can be affected by temperature, wind, and clouds. For example, if the temperature outside is warmer some objects will be about the same temperature as a human.  While this doesn’t render the thermal scope completely useless. It can make distinguishing between objects more difficult.

The wind has a bit of the same effect, although not as drastic as the temperature. It can cause a bit the image produced by the scope to be a bit blurred at high winds. This mixed with an ambient temperature around body temperature can make images from thermal scopes very difficult to interpret. 

Clouds are interesting while using thermal scopes.  In fact, if the day is cloudy it will improve the performance of thermal scopes.  Since the clouds will absorb some of the sun’s radiation. Inanimate objects will not be as hot. Living things that produce their own body heat will stick out more against the cooler objects.

Price

Unfortunately, the price will always play a role in selecting which option fits best. Thermal and night vision scopes for some hunters are a luxury and others are essential depending on the animal you are hunting.

For police and military, these scopes are essential to protect lives. Thermal scopes tend to be a bit pricier than night vision scopes, but some consider the extra price worth it. A few top models are listed and compared below.

Night Vision Scopes:                                                 

Model

Cost

Firefield FF26014T

$600

Sightmark SM18008

$515

Firefield FF16001

$270


These options for night vision are on the higher end of the options available to the public. They come with features such as WIFI compatibility, capturing video, and calculating bullet drop. An interesting ability of the Firefield FF26014T, it can read infrared waves for a short burst of time to help differentiate between leaves and a boar. The higher-end models can come with bright light protection as well.

Thermal Scopes:

Model

Cost

ATN X-Sight II HD 5-20

$699

ATN Thor HD 384

1,1376

The options for thermal scopes are more expensive than their night vision equivalent.  The thermal scopes come with ballistic drop, wind affect calculators, image stabilization, GPS, and a range finder. The extra cost is attributed to the relatively new technology of thermal imaging when compared to night vision.

Night vision has been in devolvement for military purposes since world war two by the Germans. While thermal scopes weren’t used by the military of any country until the late 60s. Due to the different times of discovery, there has been a lot less commercialization of the thermal scope until relatively recently.

With any luck, thermal scopes will follow the trend of night vision and drop significantly in price within the next 20 years. Of course, cheaper options can be found for both night vision and thermal scopes, but due to the complexity of the device going for a scope a cheaper scope might not be the cheapest option.

The Internet is full of heart-wrenching stories of a buying a 300-dollar thermal scope only to have it fall apart within the year. So, if you are going to splurge on a way to see in the dark, you might as well shell out a bit of extra cash to get a better model.

Scope Specs

To help the reader further navigate the complex waters of buying a thermal or night vision scope, and to make sure, you are purchasing the right scope before shelling out hundreds of dollars. The following specs must fit the application you intend to use the sight for.

Resolution of the sensor or scope: The clarity of images seen in the scope

When buying a thermal or night vision scope be aware of both the scope and sensor resolution. If the scopes’ resolution is much higher than the sensor. You are paying for scope resolution you won’t see as the sensor won’t get the image resolution near that at which the scope can produce.

Magnification: The scopes ability to enlarge objects

The magnification of a regular scope is straight forward. However, a higher magnified thermal or night vision scope can affect more than just the clarity of the images.  One needs to remember that before the user sees the image. The light or infrared going through the lens of must be processed by the microprocessor in the scope.

A higher magnification can lead to longer processing times and a reduced refresh rate. It is important to buy a scope with only as much magnification as you will need to help reduce the effect of magnification on other specifications. This can keep the price down as well.

Scope Detection Range: Distance at which the scope can identify a target

As was discussed above a lot of factors can affect the performance of a thermal or night vision scope. This rating provided by the manufacturer might be a result you will never achieve in the field, but a buyer can use this rating as a baseline to compare different scopes.

Refresh Rate: The speed at which the screen updates

This is essential for tactical and home defense use.  A faster refresh rate keeps the user more informed of movement downrange. While a hunter might not need to be instantly aware of movement. Anyone trying to identify a threat must be. A faster refresh rate often increases the price of the scope by a significant amount but is worth the extra money.

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