The number of specifications listed for a thermal camera can be overwhelming when trying to find the right camera for your needs. Any one specification in isolation will not tell you much about the camera; instead, it is a combination of factors that determine the capabilities of a thermal imager. All of the specifications provide useful information, but these are the main ones you should consider to make sure you buy the right camera for your application. That's why we list the 6 specifications to consider before buying a thermal imaging camera.
1.- Range
The range is the full scale of temperatures at which the camera is calibrated and capable of measuring. Some cameras have multiple ranges to more accurately measure a wider range of temperatures. Know the temperatures you are likely to encounter in your application: selecting a camera with a higher temperature range is especially important for certain industrial applications, such as measuring high-temperature equipment, e.g. boilers, furnaces or ovens.
Field of View (FOV) (FOV)
The field of view is determined by the camera lens and is the extent of a scene that the camera will see at any given time. For close-up work, you need a lens with a wide-angle field of view (45° or more). For long-distance work, you need a telephoto lens (12° or 6°). Some cameras may be available with multiple lenses for different applications.
3.- IR Resolution
Camera resolution is the number of pixels the camera has in the scene. Higher resolution means that each image contains more information: more pixels, more detail, and a higher probability of getting an accurate measurement. Depending on your application, especially when you can get close to the target, you may be able to choose a lower resolution, lower cost camera. Measuring smaller targets from farther away will require higher resolution.
4.- Thermal sensitivity (NETD)
The thermal sensitivity or noise equivalent temperature difference (NETD) describes the smallest temperature difference you can see with the camera. The lower the number, the better the thermal sensitivity of the infrared system. A word of caution: cameras from low-cost manufacturers may hide poor sensitivity by taking NETD at 50°C instead of the industry standard 30°C. If the targets you need to measure typically have large temperature differences, a camera with a low NETD is probably not necessary. However, for more subtle applications, such as detecting moisture problems, you will need more sensitivity.
5.- Focus
Cameras can have fixed focus, which means they are always in focus; have manual focus, which means the user adjusts the focus on the camera; or autofocus, which means the camera will automatically focus based on what it can see for the contrast of the scene. In general, entry-level cameras will have fixed focus and high-performance cameras will have either manual or auto focus. The advantage of manual focus over auto focus comes down to the needs of the user.
Spectral range
The spectral range is the range of wavelengths detected by the camera's sensor, measured in micrometers (µm). Most gas detection cameras (such as propane, methane and butane detectors) are medium-wave cameras, meaning they have a spectral range of 3 µm to 5 µm. Almost all other thermal cameras are longwave and have a spectral range of 8 µm to 14 µm. Longwave cameras are suitable for most other applications, from electrical inspections to fire suppression.
In conclusion, keep these important specifications in mind when determining which thermal imager is best for your needs. Remember, looking at just one specification value will not give you a good indication of a thermal camera's capabilities. For example, if you need to detect subtle problems such as moisture, having a high resolution will do you no good if the camera does not also have a high thermal sensitivity.
If you need a place to start, check out the FLIR Exx series for a good general purpose handheld camera. For long-distance electrical or utility work, check out FLIR's T-Series, and for close-up work or for an entry-level option, consider a lower-cost camera like FLIR ONE Pro or FLIR C3.
If you are still in doubt, our consultants can advise you on which type of thermal imaging camera best suits your needs.
Related entries
Industrial maintenance, from cost to strategic investment
For decades, industrial maintenance has been perceived as a necessary evil. An activity primarily aimed at complying with regulatory requirements, avoiding penalties, and responding to
Thermography applications in industry
All objects around us emit infrared radiation that can be captured and visualized with a thermographic camera. Thanks to this physical property that provides us with thermal information, we can apply infrared thermography to an infinite number of sectors. Discover examples of the most representative applications below.
Risk prevention in ATEX Zone 22 with FLIR Si2x
FLIR Si2x, the key to detect hazards before it's too late. In ATEX Zone 22 environments, where combustible dust can become a latent hazard, this innovative acoustic camera can locate air leaks and mechanical failures without stopping production, ensuring safety and operational efficiency.