The largest thermal camera I looked at was the Flir One Gen 3, which is about 2.6 inches wide and 1.3 inches tall and has a built-in battery and two cameras. It’s the most complex camera I’ve looked at. This large camera body has rounded edges, two rubber grips on the side, and a Lightning plug on the top, which is the only thing holding it in place.
The Flir saves images at a very high resolution, but that is a bit of a trick. Perhaps cheat is too strong a word, but some sleight of hand is going on here. The sensor only captures a small amount of data. To create the higher resolution image, the device smooths and scales up the thermal image and combines it with a much higher-resolution visible light image from a second camera. You already have multiple cameras on your phone, but this device will add two more.
It works even though it may be a bit stealth. The visible light camera adds a ghostly edge-drawn effect to the image that can be very useful when trying to locate a heat source, such as which side of a window is leaking warm air or which component on a circuit board is overheating.
There is a downside to this complexity. The extra battery in the camera is located on the bottom of the device and needs to be charged through the USB-C port. The camera won’t work if you don’t charge it. To turn the camera on, you have to press a button at the bottom of the device, then wait 20 seconds for the Flir One app to detect the camera. The images you get are great, but it all feels overcomplicated compared to the other cameras, and it is one more device to keep charged
The problem with the thermal cameras is that they plug into the phone’s charging port, which requires a tight fit to work. If you have a case on your phone, you may not be able to plug it in fully. A nice solution is to twist the wheel under the plug to make it move up and down, so that it can adapt to different phone cases. To use the Seek Thermal and Prime Perfect cameras, I had to take the case off my phone or use an extension cable because the plug couldn’t be fully clicked into the phone’s sockets. The case on my Fold 4 worked with the One Gen 3.
