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Features of a Thermal Optic Scope: Which Are Important?

L.p. Brezny | Updated February 26, 2024 | Why You Should Trust Us | How We Earn Money
cover photo of thermal scope features showing the parts of a scope, article title, and logo

Some of today’s thermal gun scopes seem to do everything but pull the trigger for you. Do you need a feature-packed scope? Do you need a bare-bones scope?

Best Thermal Scope Features

The best thermal scope features are the ones you need, followed closely by ones you want and, in a distant third place, features that might be used. 


Warranty leads the list of top features of a thermal optic scope. Why? Because thermal scopes are packed with electronics. The warranty means the company will either fix the scope or replace it for you.

The industry standard warranty is 3 years. The top scope makers offer this. If you get a scope that does not have this warranty and you bought the item on Amazon, you can buy a warranty through Amazon.

The Amazon warranty will not extend the manufacturer’s warranty, so do not buy this if the scope comes with a 3-year warranty.

Battery Life

Computer screen showing red battery life indicating low

Some people might say this is less important than the warranty. It is a top feature because the battery is the power source for your scope. Dead battery = dead scope.

Batteries for thermal optics can be internal or replaceable. Get a scope that allows you to swap batteries. This matters because thermal scope battery life varies. Some scopes promise up to 10 hours of hunting and some as little as 4. The more things you do with the scope, the faster the battery drains. 

Running the scope and other features at the same time will run out the power faster than just using the scope. Also, battery drain is higher in cold weather.

If the scope has an internal, non replaceable battery, then you have to plug the scope into a power source to recharge it. That same external power source may be able to run the scope.

Exchangeable Batteries 

Carrying an extra battery pack is something else to haul and keep up with. The power cord can get in the way. 

In the long run, rechargeable lithium-ion (LI) batteries are more expensive than high-quality single-use alkaline batteries. However, the ability to recharge the batteries means they are much cheaper in the long run. You can even buy a vehicle charger to have the batteries juice up while you hunt and drive around.

Replaceable batteries vary from the disk-style to the tube-style. The is the most common battery for thermal scopes. 

Before you buy extra batteries, make sure what battery the scope needs. Some scopes use a proprietary battery pack like the Pulsar Trail 2 LRF. You have to order Pulsar’s battery pack and charger to have extra.

Sensor and Refresh Rates

You may wonder why a sensor and something called refresh rate are important. Both speak to the performance level of the scope. Better sensors and higher refresh rates mean the scope works better.


The sensor in a thermal scope is measured in microns, abbreviated as um and 1 millionth of a meter. To explain why requires an involved explanation of the sensor manufacturing process. With a smaller sensor number, you can get better detail in the image through the scope and see farther away. (1)


Refresh rate is easier to understand as important. Short version – refresh means how fast the screen in the scope is able to change the picture. 

Long version – refresh rate matters because if you are tracking a moving object, the screen has to update the image. It can freeze between updates. Faster refresh rates, measured as hertz abbreviated as Hz, mean the scope can follow a moving target better. Top thermal scopes are 60Hz.


Image of large zoom camera lens

Magnification in a thermal scope comes in two types, digital and zoom.

Digital magnification takes the image and enlarges it like blowing up the picture on your smartphone or computer. As you make the picture bigger, the pixels making up the image also get larger. You lose resolution. It is not a true zoom.

Zoom means the scope’s lenses magnify the image, just like in a traditional scope. Zooming in means the pixels stay the same size while the image you see increases. You do not lose resolution.

Scope Detection Range

Flir thermal camera looking at a computer screen

Scope detection range is for far away a heat source can be before the scope sees it. Most thermal gun scopes today can pick up a heat signature at 2,000 or so yards. A longer detection range is better.

Identification Range

The identification range is directly linked to the detection range. Good thermal gun scopes can let you identify a heat source the size of a person or deer accurately at around half the full detection range. Example: The scope has a detection range of 2,000 yards. You can reliably identify a human or deer at 800-1,000 yards.

Bigger heat sources can be farther away. Smaller heat sources must be closer. For instance, in the scope just above, you could expect to ID a coyote, fox or something similar at 500-600 yards. (2)

Features You Find Useful

Now we move into the thermal scope features you will find useful. These are not necessary. Some, like a rangefinder and a ballistic calculator, help you be a better shot. Some like a video recording feature are just fun because you can record your hunt and play it later to relive the hunt.

Range finder

A range finder tells you how far away your target is. Some thermal scopes have this as an integrated feature. In others, you can add the range finder. Knowing the difference between 100 yards and 125 yards matters, especially when you are using slow-moving bullets like a 9mm or .45-70. Three inches of bullet drop is the difference between a miss and being on target.

Ballistic Calculator

Ballistics calculator

A ballistic calculator also improves your ability to shoot accurately. It shows you where to center the reticle for the best shot, based on the distance and the wind. It is commonly used with a rangefinder to get the most accurate distance measurement.


Many thermal scopes today allow you to record the hunt with a built-in video camera so you can enjoy watching it over and over from more comfortable surroundings. You can even share the video online.

Generally, if you can shoot video with the camera, you can also take still pictures.


Image of a typical scope reticle

High-end thermal scopes give you reticle choices. You can use the standard horizontal and vertical wire or go to a dot in the center, a Christmas tree reticle with hash marks on the windage and elevation bar or something else.

If your scope has a ballistic calculator, the scope will show you where to aim. If you have the Christmas tree reticle up, aiming is even easier because the scope will show you which hash marks put the bullet on target.


An eyecup is a flexible, soft rubber extension coming off the scope. It is supposed to fit around your eye. The purpose is to stop ambient light from spoiling your view through the scope. Most eyecups are contoured to curve around your eye, which means if you wear glasses, they get in the way. Eyecups are only needed when hunting with a thermal during the day.

Wireless Bluetooth 

Wireless connections to your thermal scope are handy. It can be a WiFi or Bluetooth. Either way, you can connect the scope to an electronic device like a smartphone while in the field. You can record video and still images with your smartphone directly from the scope’s feed. You can also download anything you recorded.

A few scopes also have a GPS tracking system that allows you to know where other hunters are located as well as any dogs wearing tracking collars. That is very handy when trying to find people or dogs on a dark night.

Quick Release 

Image of quick release

Quick release means the scope mounts to the Picatinny rail with a lever clamp, which are common on most AR15 rifles. Push the lever to tighten the scope to the rail. Pull to release the scope. It is easy to move the scope from gun to gun and remove it to store the scope separately from the gun when not hunting.

Best Thermal Scope accessories

The best thermal scope accessories start with extra batteries if your scope allows this.

A set of lens covers keeps dust off the glass. The covers also prevent the scope from being flashed accidentally by the sun. The sun is so hot. Even though it does not feel that way to you, it can damage the sensors inside the scope.


If you remove the scope for storage, a case is always a good idea. It protects the scope from accidental damage if it is dropped or bumped off a shelf inside your gun safe when you reach for something else.

How Long Do Thermal Scopes Last?

Thermal scopes with lots of features tend to be much more expensive. So you might be asking yourself, how long does a thermal scope last with normal use? We

More Reading: Best Budget Thermal Scope

best budget thermal scope

If you’re looking to hear more about specific optic recommendations, check out our article on the best budget thermal scope picks out there. We go into detail and explain which one of these features are worth it and which you can go without.


  1. Seeing in the Dark: A History of Night Vision from Smithsonian Magazine – https://www.smithsonianmag.com/innovation/seeing-dark-history-night-vision-180963357/
  2. Thermal Imaging: How Does It Work from Tech Briefs – https://www.techbriefs.com/component/content/article/tb/supplements/pit/features/technology-leaders/26470

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