It is the nature of the predator to hunt at night. Prey is vulnerable and the predator remains hidden, this is the ultimate advantage. Man has always had weak night vision, the weakest in the animal kingdom. Luckily, we have technology now that can change that.
How They Work
Night vision should more aptly be called light amplification. It takes very dim light magnifies that to make the image brighter. There are two different technologies used for this. Traditional night vision is a very complicated technology that can be quite expensive. It works using a photoreceptor that converts light into electrons which are then fired at a cathode screen. This creates that bright, green image we are used to seeing.
Rather than visible light, thermal scopes use thermal radiation emitted from all warm objects to highlight them against a cooler background. The technology is complex but the basic theory works much the same way as a traditional night vision scope. A thermal detector picks up any heat sources and coverts that through an image processor into something visible to our eyes.
Pros and cons
- Far cheaper, especially digital
- Natural looking images
- Can see terrain, animals, and surroundings
- More Durable, especially traditional night vision
- Animals can blend in
- Shorter range
- Needs external light source
- Traditional night vision will burn out over time
- Cannot see through fog, mist, and smoke
- Night use only for traditional night vision and some digital
- Warm objects and animals stand out
- Exceptional Range
- No need for light source
- Can see through smoke, fog, and even some foliage
- Possible to see heat signatures left behind like tracks or bedding areas
- Can be used day or night
- Multiple display modes
- Images can be confusing and hard to interpret
- Cannot see cold-blooded animals, terrain
- Usually larger and heavier
Night visions major strengths lie in the slightly simpler technology that is more durable and uses less energy. Night vision is easier to read since all surfaces reflect light to some degree. This means you can see all of the terrain and surroundings in your area.
Night vision can cause eye strain, especially traditional night vision. The images are often brighter and will ruin any natural night vision when you are not using the scope. Despite a brighter image, night vision often has a superior battery life, especially if you get a model that allows for an external battery pack.
More companies make night vision technology. The market has more innovation and competition which makes improved technology available at a cheaper price. This also means there are more accessories for night vision.
The range on traditional night vision is quite good but range for digital night vision is much shorter, usually around 100 yards. This limitation is simply a restriction of how far the fainter light travels. The sensor can pick up at long range but you can’t get enough light out far enough for the scope to pick up long distance.
Night vision technology is smaller, lighter, and more durable overall. This is especially true of traditional night vision. Digital night vision is still less sensitive to the elements and breakage and can be serviced more easily.
Thermal Imaging is great for picking out specific targets against a cooler or warmer background. Most units have a variety of ways to display this data and many are much easier on the eyes than night-visions harsher contrasts. They may still ruin your night vision but are much less likely to cause severe eye strain.
The technology used in thermal imaging does use more power and often has less battery life if you have planned for a whole night of hunting. This is a tradeoff for much greater range of a thermal scope. The sensors are very sensitive and thermal radiation travels much farther than the light used by regular night vision.
With a thermal scope, the only difference in shading is temperature so you often won’t be able to make out terrain, background or anything else unless it has a different temperature gradient. Most of the world will become a flat background and only a warm-blooded, living thing will really stand out. This is a benefit and a drawback.
Very few companies have made the investment to produce thermal imaging scopes. This means less market competition and higher prices. Almost all thermal scopes use the same detector made by one company who does offer a great warranty should anything go wrong. The remainder of the scope is produced by a different manufacturer that may or may offer a warranty and/or repair service.
Overall, thermal scopes tend to be on the less durable side and are large and heavier than most night vision scopes. We are just getting to the point of the technology where size is decreasing but this means that cost is going up as the devices get smaller.
Deciding between Thermal and Night Vision
If you are in the market for one of these technologies, there are a few points to consider before making your purchase. With a good understanding of the limitations and strengths of each, you should be well ahead of the curve but here are a few of the main points you are likely to run into.
Knowing where you plan to use your scope will give you a better chance of making the correct decision. If you are in a more open area with clear conditions and short to moderate ranges, there is no reason that a night vision optic will not work for you. Whether you go with traditional night vision or digital is up to you but either will tend to work well.
For areas with thick undergrowth, dense foliage, fog and other obstruction to light, a thermal scope will greatly improve your chances of seeing your target. Since they are not impeded by any of these barriers to vision you can confidently make out targets that would otherwise be invisible.
The same is true for range. If the ranges you are planning on using your scope are farther, you are probably better off with a thermal scope. They greatly outdistance digital night vision and are generally better at making out targets at range than traditional night vision.
Digital night vision is far more affordable than any of the other technologies, often costing only a small fraction of the price. This does indicate some of the issues with this technology and its limitations but for use in hunting and around the home, most people find this to be a perfectly adequate technology.
Traditional night vision comes in several generations and each increases in cost by a huge margin. First Gen and some Second Gen scopes can be purchased for relatively affordable prices but most Second Gen and all higher end night vision can be very expensive.
Thermal scopes tend to start out quite expensive to begin with but never reach the cost of a higher generation night vision. You can get most any digital night vision scope for less than thermal but even a cheaper second gen scope will be on par in cost.
The fact that should always remain foremost in your mind is that any night vision scope requires light of some kind. There has to be reflected light in order for the technology to work. Thermal has no such limitation and relies on light emitted from the target.
As a point to consider, if you will be using your scope in areas with no light thermal is your only viable technology. These areas are rare but the point is worth considering.
Deciding between digital and traditional night vision has a similar issue. The detector in a traditional night vision scope picks up smaller amounts of light that in the natural environment and uses that for illumination. The detectors on digital night vision are not so sensitive and almost all of them require some form of artificial IR light to function.
Most digital night vision have these IR emitters onboard but a few will require you to provide your own. While they are not expensive it is an inconvenience and something else to find a way to mount on your rifle. This may or may not be an issue depending on the rifle platform you use and its mounting points.
That covers the dark but what about when ambient light is higher? It isn’t likely that you will need night vision in brighter conditions but thermal can still have some applications.
Traditional night vision completely washes out in the light at the best. If you get some lower generation night vision scopes they can even burn out completely and will never function again. This can happen from daylight or a random point source at night. This is a distinct limitation of traditional night vision only.
Most digital night vision will function in any light level and most can be used as a full-color scope in broad daylight. This adds a little versatility even if the scope will not provide any assistance in locating targets.
Thermal works both night and day and will function the same either way. Light has no effect on thermal so you will still see the same gradient images. During the day, the sun can heat some surfaces casing them to mask other heat sources. Conversely, surfaces that stay cooler like vegetation will still stand out against a warm body. This makes the technology viable at any time in any conditions.
Starting with traditional night vision, you will get nothing more than the scope in almost every case. Very occasionally you may find a traditional night vision scope that uses phosphor awhich changes the image from green to grey and causes less eye strain. This will add to the cost and may be of limited benefit.
The real stars when it comes to accessories are the digital night vision scopes. Because they work using a video feed, it is common to find them with the ability to record and even stream video over wi-fi. This may be a bit gimmicky but many hunters have used this to capture the excitement of their hunt and share it with others. It is also possible to stream your scope straight to a smart device so your spotter can see exactly what you are looking at.
Many thermal scopes are made by the same companies that make night vision scopes so you will get similar features. This means you may find them with recording features and wi-fi streaming or get them as a bare-bones scope. This depends on the manufacturer and, as far as thermal goes, the price does not differ much whether you have this technology or not.
Though the market for civilian night vision and thermal optics is almost completely dedicated to hunting, that is not the only possible use. It does excel for those purposes and there are uses for both technologies by the modern hunter. Typically, you see these used for hunting hogs and coyotes that can legally be shot after dark. Occasionally deer can be taken with these optics when light conditions are lower at dawn and dusk.
That use aside, you may also opt to use either technology around the home. Both are quite good at ridding your property of destructive varmints should you live in a location where that is possible and legal. The modern homesteader has found that night vision and thermal technology are a great way to protect their livestock from predators.
The same technologies can be used to keep your home safe from other intruders. The ability to see in the dark is quite powerful and usually beyond the reach of the common miscreant. While this does not condone actively attacking someone in your home, the ability clearly to see them while taking appropriate action can help keep your family safe.
If you do choose a technology for home defense, it would probably be best to go with night vision. While thermal is potentially better at spotting a target, it gives you no details of what that target looks like other than general shape. Night vision, especially digital night vision, can tell the difference between a friend and a stranger. This technology also gives you the ability to record their actions and the details about them in case that is ever needed for any legal proceedings.
Thermal in such a situation would be worse than useless. It would tell you that something warm and human-shaped was there and that is all. Should you take any action that resulted in injury or loss of life of an innocent person, it is likely that the use of thermal would be considered negligent by authorities.
As a primer on the differences between the two technologies, this is a scratch on the surface. It is intended to be practical more than scientific. You can find tons of documentation on the minutia of how the technology works but those are not helpful unless you are already beyond the scope of what this article offers. They don’t give specifics of when and where each technology is applicable, instead opting to detail the way the devices function.
Hopefully, this article fills the niche between what is readily available about specific products and the technical documentation. The whole goal is not to provide a ‘how it works’ document but instead to help with decision making if you are in the market to purchase one of these amazing pieces of technology.