Professionals in construction, medicine, and aviation use dedicated thermal cameras that can cost thousands and even tens of thousands of dollars. That's too much for the average handyperson, hobbyist, or aspiring ghost hunter. That's why Flir offers thermal camera phone attachments for a fraction of the price of dedicated cameras. The third-generation Flir One is the most affordable at $200, while the $400 Flir One Pro is easily the most powerful consumer-level model thanks to its advanced metering features and higher resolution. The $299.99 Flir One Pro LT is a solid compromise between the two, combining the thermal core of the Flir One with the software features of the Flir One Pro for a functional middle ground at a reasonable price.
The Flir One Pro LT is physically identical to the Flir One Pro. It's a rugged-looking, chunky black rectangle with metallic side panels and rubberized top and bottom panels. The top panel holds the phone connector, which is USB-C, micro USB, or Lightning depending on the version you buy. This plugs into the bottom of your phone so the camera can work. Don't worry if you have a case; a mechanical wheel below the connector can extend it up to 0.3 inches, letting it plug in even through rugged phone cases.
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The bottom panel of the Flir One Pro LT holds a power button and a USB-C connector for charging the camera with the included cable (it doesn't come with a wall adapter, so you'll have to use your own or a spare port on your computer). The device runs on its own internal battery power, which according to Flir will allow thermal imaging for up to an hour before it needs to be recharged for 40 minutes. Besides the charging cable, the Flir One Pro LT includes a hard, zip-up case.
The front panel holds the two cameras. One is an 80-by-60 thermal core that performs the actual thermal imaging by detecting infrared radiation and measuring temperatures between -4 to 248 degrees Fahrenheit. The other is a 1,440-by-1,080 visual camera that works with the thermal core to provide more detailed pictures using Flir's Multi-Spectral Dynamic Imaging (MSX) image processing. The thermal core is the biggest difference between the Flir One Pro LT and the Flir One Pro; the more expensive One Pro has a 160-by-120 thermal resolution and can measure up to 752 degrees Fahrenheit.
To use the Flir One Pro LT, you need to install the free Flir app for Android and iOS. It serves as the camera app for the device, processing both the thermal and visual information the two sensors record. By default, the app opens in a live camera view that shows the thermal image augmented with translucent lines indicating the contours of objects the higher-resolution visual camera can see. This is Flir's MSX image processing feature, which lets the app capture a fairly detailed 1,400-by-1,080 picture from an 80-by-60 thermal core. The detected contours help better define and identify individual objects and parts against the more vague shapes and blotches of the thermal camera.
As for those shapes and blotches, the default mode is the orange-and-purple Iron palette, but you can choose from eight other color palettes to better bring out specific highs, lows, and contours of the thermal image. They include five additional color selections (Rainbow, Contrast, Arctic, Lava, and Wheel), grayscale, and grayscale where the coldest object in the frame is highlighted in blue or the hottest object is highlighted in red.
The Flir One Pro LT has the same suite of very useful imaging functions as the Flir One Pro, starting with the ability to switch from MSX view to the thermal or visual views with a swipe. This can help identify specific sources of hot and cold if MSX isn't cutting it. You can also bring up a scale on the side of the screen showing the range of temperatures the camera is picking up, and even drag those temperatures up and down the gamut of your selected color palette to bring out specific ranges. Multiple metering options let you measure the detected temperature of any object in frame with a spot, a larger circle, or a rectangle, all of which you can drag around with your fingertip. These are all very useful functions that the non-Pro third-generation Flir One lacks.
The app lets you capture still images, videos, and time-lapse recordings. Videos are saved as standard MP4 or MOV (depending on Android or iOS version) files, but still photos retain much more information. All thermal data is stored for each photo in the Flir app, letting you adjust them just as if you were adjusting the live view. You can change palettes, set temperature ranges, meter specific points, and even switch between MSX, thermal, and visual views of any photo you shoot with the Flir One Pro LT. When you capture an image that has the information you want in it, you can then save or share it as a standard JPG with any other app or service on your phone.
Left to right: Flir One Pro LT, Flir One Pro
As a step between the Flir One and Flir One Pro, the Flir One Pro LT lacks the latter's higher resolution and thermal range. The Flir One Pro's thermal resolution is 160 by 120, four times the number of thermal pixels as the Flir One LT or Flir One. That higher resolution helps make shapes actually look like shapes and not just vague blotches, with or without MSX. The Flir One Pro LT still shows a very useful thermal image, just like the Flir One, but it isn't nearly as detailed as the Flir One Pro. The other advantage of the Flir One Pro, the higher maximum temperature, is less helpful than the increased resolution except for specific tasks involving very hot objects.
A Handy Compromise
The Flir One Pro LT is a very useful tool for handypeople, or anyone who might have to deal with plumbing, construction, or electrical wiring. It offers affordable thermal imaging and a powerful selection of measuring and metering features, ideal for finding leaks, shorts, drafts, and possibly ghosts. Those extra features make it more useful for actual repair work than the Flir One, for a modest $300. It only has a quarter of the thermal resolution of the Flir One Pro, though, so serious fix-it folk might want to consider shelling out the extra $100 for the high-end model, especially since it's still much less expensive than a standalone professional thermal camera.
Flir One Pro LT
(Opens in a new window)See It$299.99 at Amazon(Opens in a new window)
Functional thermal imaging.
Useful software features including multiple metering modes and adjustable temperature scales.
Lower thermal resolution than Flir One Pro.
The Bottom Line
The Flir One Pro LT camera accessory offers thermal imaging with some powerful metering options.
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A: The FLIR ONE and FLIR ONE Pro LT can be used in temperatures from 32°F to 95°F (0°C to 35°C) and can detect temperatures from -4°F to 248°F (-20°C to 120°C). The FLIR ONE Pro operates at 32°F to 95°F (0°C to 35°C) and can detect temperatures from -4°F to 752°F (-20°C to 400°C).
FLIR thermal camera with screening mode can achieve accuracies of ±0.3°C (0.5°F) at the recommended ambient temperate of 30°C to 45°C (86°F to 113°F).
The FLIR ONE Pro is tuned to align thermal and visual images at a distance of 3 meters.
The FLIR ONE Pro helps you find invisible problems faster than ever, whether you're inspecting electrical panels, troubleshooting mechanical systems, looking for HVAC problems, or finding water damage.
Overview. The FLIR ONE for iOS Thermal Imaging Camera, in combination with its free app, transforms your iPhone or iPad into a powerful thermal imager.
A: The FLIR One & FLIR ONE Pro battery lasts about 45 minutes when being used continuously.
The Bottom Line. The Flir One Pro is the most powerful consumer-level thermal camera accessory available, with remarkably high resolution and temperature measurement. PCMag editors select and review products independently.
No, thermal cameras cannot see through walls, at least not like in the movies. Walls are generally thick enough—and insulated enough—to block any infrared radiation from the other side.
FLIR thermal cameras work both day and night, regardless of light. They're totally immune to the effects of darkness, glare, or even direct sunlight.
Plug the Lightning USB end of the power cable into the FLIR ONE and plug the other end into a 1A power source. The Charge Indicator LED will blink while the device is charging. The FLIR ONE requires less than one hour for a full charge (with a 1A source).
Thermal sensitivity, Noise Equivalent Temperature Difference (NETD), describes the smallest temperature difference you can see when using a thermal device. In effect, the lower the NETD value, which is measured using milliKelvin (mK), the better the sensor can register small temperature differences.