Top 10 Best Budget Thermal Imaging Cameras

Viewing distance

Viewing distance will determine how near you must be to an object to conduct the thermal sensing and imaging. You should expect that, as distance increases, detail decreases. Distance also factors in from the opposite sense – you want to stay a minimum distance away from extreme sources of heat, for instance.

Thermal image resolution

This will be expressed in pixels, with the greater the number of pixels equating to more detail in the on-screen image. Your application will determine the resolution needed. For example, if checking window seal leakage, you will not need deep resolution, while you would if looking for an overheated wire within a motor.

Display screen

The combination of pixels and display screen size will determine the level of detail in your final image. Many models will also give you the option of downloading the images to a computer or tablet for optimal viewing size.

Durability

In many cases, these thermal imaging cameras will be used in outdoor or other rugged environments. Some manufacturers will conduct drop tests to use as one measure of the durability of the camera. Materials of construction will also factor in, where engineered plastics will offer greater strength than some other composite materials.

Thermal sensitivity

Thermal sensitivity is the smallest temperature difference that the camera can detect. Sensitivity will normally be expressed as +/- a number of degrees in the Centigrade or Fahrenheit scale.

Temperature range

Each thermal imaging amera will have a range of sensitivity, ranging from the lowest temperature to the highest. Some cameras will be more sensitive at the lower end; for example, those used in refrigeration applications. Cameras used in fire fighting situations would need a higher end temperature range.

File format

Many of the thermal imaging cameras will capture the images, typically through built-in memory or supplemental SD cards. For the greatest flexibility, downloads should be in a format compatible with other devices, such as computers. JPG formats are most common for this type of application.

Reporting

Some thermal imaging cameras allow you to create and export reports, including captured thermal images, in either PDF or DOC formats. This feature is probably most useful for those using the camera professionally, so they can make a presentation to potential clients after doing an evaluation.

Weight and ergonomic considerations

These units are typically very lightweight, with several weighing less than a pound. However, if you are a professional, and going to be using the thermal camera extensively, it is wise to consider the overall weight and ergonomic features of the unit. Consider how the unit is held and operated, as that will impact strain on your hand, wrist, and fingers.

Options

Commonly available options include carrying cases (both soft and hard-shell), stylus/pens for touch screens, moisture testing kits, voltage testing kits, and rechargeable batteries.

Field of view

Field of view is the observable area you can see through an optical device such as a thermal camera. If you imagine a straight line through your body as you look in the viewfinder, that would be a 180^o field of view. Most of these cameras will be in the range of 30^o – 50^o.

Warranty and technical support

Check the manufacturer’s warranty for the base term, and also look into extended warranties, particularly if you are buying a more expensive unit, versus a low end “throw-away” camera. Check technical, operational documentation available, and look into human support in the event you have questions not found in the documentation.

While you would expect some additional functionality in the more expensive unit, such as moisture reading or voltage measuring, the primary difference you will see is in the picture quality, or resolution, of the displayed image. Resolution is defined by the number of pixels. A pixel is the smallest image that a device is able to print or display. So, the greater the number of pixels, the clearer the object will be on the viewing screen. Some cameras have as many as 76,800 pixels, while cheaper models may have only a few thousand pixels.

Since thermal cameras measure a difference in heat, one of the more common applications at home is looking for heat loss. For example, if you point your camera at a wall or ceiling location, and see a hot spot, that would be a good indication that a lack of insulation is heating up that spot more than other areas. Similarly, if you see cold air leaking around a door or window in the winter, it could mean that your insulation or weather stripping is failing and letting in cold air.

They can also be used for more mundane tasks, like trying to find your dog in the dark (his heat signature will be different than the ambient temperature). You could check food temperatures to make sure they have reached a safe level for eating. You could even use it to find the coldest bottle of beer.

The light waves required to shoot photos with a regular camera will filter through the standard glass, so the lens cost on a regular camera is a relatively minor part of the total cost. However, the infrared rays read by a thermal camera will not filter through a normal glass lens. A special lens is required, typically using rare materials such as germanium, calcium fluoride, or crystalline silicon (Wikipedia.com), and then an anti-reflective coating is applied to the lens. This makes the cost significantly higher than a camera lens.

The thermal imaging cameras featured in this review qualify as “budget” cameras, as all of them are priced under $500, with some just over $100. However, if you want to buy the best of the best, you could expect to pay $8,000 – $10,000 for a high end, top-quality camera. In fact, some cameras for specialty applications, such as a combined thermal and night vision camera for marine tracking can cost as much as $85,000.

It’s big, and it’s likely not very far into the future. Thermal imaging technology is being used in driverless car systems which are under development by several manufacturers from all over the world. These imagers would sense upcoming temperature changes, which would be indicative of another car, pedestrian, cyclist, barricade, and so on. The cameras would feed data to the computer systems and trigger actions such as stopping, slowing or turning. Because these cameras are thermal, they also work in challenging environments like smoke, smog, darkness, fog, and glare (Flir.com).