FLIR ONE Gen 3 – iOS – Thermal Camera Review

Written By Kim Goodwin is reader supported. When you buy through links on our site, we may earn an affiliate commission at no cost to you.

Flir has always been one of the top brands in the world of thermal cameras. As expected, the Flir One Pro Gen 3 comes with the top class performance that we expect from the brand. Moreover, it scores over the Flir One and the Flir One Pro LT in terms of image resolution and overall performance. 

If you think that thermal cameras offer poor image resolution, the Flir One Pro with its 19,200 pixel resolution will make you think again. In addition, it can measure higher temperatures from the previous generation cameras from Flir. 

Admittedly, it is not perfect. But it hits the mark when it comes to image quality. Basically, this smartphone attachment is designed not just for hobbyists, but also for professionals.

We always ensure thorough testing of each product that we review. For the Flir One Pro review, our team of experts used it in a variety of conditions to check how it fares in the real world. In the next stage, we also took feedback from the long-term users to ensure that this Flir One Pro review delivers the exact facts.

Let us dive into the details of this Flir One Pro review to discover more.

FLIR ONE Gen 3 – iOS – Thermal Camera for Smart Phones



  • Thermal Resolution: 80 × 60 pixels
  • Visual Resolution: 1440×1080 pixels
  • Field of View: 55 x 43°
  • Focus: Fixed 15cm
  • Frame Rate: 8.7Hz
  • Thermal Sensor: Pixel size 17µm, 8 – 14µm spectral range
  • Operating Temperature: 0 °C – 35 °C (32°F – 95°F)
  • Object Temp: -20° to 120°C (-4°F to 248°F)
  • HFOV / VFOV: 55° ± 1° / 43° ± 1°
  • Accuracy: ±3°C or ±5%


  • Great image quality
  • Top-class design and durability
  • Impressive temperature range
  • Good compatibility
  • Allows post-capture image editing


  • The FLIR One app needs improvement
  • Battery life is not the best
  • Instructions are somewhat vague


If you want a thermal imager that is easy to carry around and much more mobile when it comes to operation, the FLIR ONE is best for you.

FLIR One gen 3 works through the free Flir thermal imaging app for android and iOS. After the FLIR one plugged into your phone, the app opens quickly to expose an image of whatever you aim the camera at. It shows a variety of orange and purple stains that are vaguely consistent with the exterior of the objects in view.

The FLIR One looks at the world with the MSX technology of Flir. Because the thermal core comes with low-resolution so, the software combines the thermal patterns it takes with the image of a nearby camera, to better define where the sources of heat and cold may be based on the definition of these visible objects.

This device’s camera is built around a lepton imaging core, with a resolution of 80 to 60 pixels. It provides smooth videos that are easy to pin down to the right information before calling a professional if needed.

Highlights of FLIR ONE Gen 3:

  • MSX Technology
  • Dual cameras
  • Save still images, video, time-lapse, and panoramic
  • OneFit adjustable-height connector
  • Latest user-friendly interface
  • Strong protective case

Why Should You Consider the Flir One Pro

There are plenty of exciting features in the Flir One Pro that made us mark it as a top pick. Let us take a closer look at some of them.

High Resolution

The main camera offers an impressive thermal resolution of 160 x 120 with a spectral range of 8 to 14 µm. On top of that, there is FLIR’s proprietary VividIR™ technology that captures more detail.

But that’s not all. There is a normal 1,440 x 1,080 visual camera on top of the thermal one. The patented MSX imagery combines a visible image with a thermal image for crisp output.

In our tests, we found the images as some of the sharpest we have seen from a mobile thermal imager. Even the minute details of the heat signatures were captured to perfection. When compared with the Flir One Pro LT the image clarity is exceptionally good – thanks to the additional pixels. 

Moreover, the superior sensitivity of the camera can detect temperature differences down to 70 mK. As a result, you get a sharp distinction between the hot and cold zones in the image.

The feedback from long term users also mentioned it can capture thermal signatures from footprints. Our test results indicated the same. So this a device campers and wildlife enthusiasts will love to use. Also, we found it working very well in complete darkness. That makes it a good thermal imaging camera for security purposes.


To start with, the chunky black body of the Flir One Pro feels solid in hand. The dimensions (2.7 x 0.6 x 1.4 inches) make it compatible with most smartphones, even though it is slightly thicker.  

The Type-C USB connector sits flush with the top panel. But you can extend it by 0.3 inches by using a mechanical dial. This is one cool feature that we loved. Most importantly, the adjustable height allows you to use the camera even with a thick casing on your phone. 

On the bottom, you get the Type-C input for charging and a power button. The camera comes with its own battery which lasted for 45-50 minutes for us with heavy use. There is no fast-charging and the battery charging time was around the 45-minute mark. 

In our tests, the standby battery life was also decent. Considering the high image quality and the advanced features, a fast battery drain was expected. Frankly, this is one area where we felt that Flir could have done better.

If you plan to head outdoors with a thermal camera, this is a good pick. With a 1.8-meter drop test rating, it can easily absorb drops and shocks. The durable rubber edges add to the overall ruggedness. However, the camera does not come with an IP rating. So be careful with it in wet environments.

On the whole, the Flir One Pro excels when it comes to hardware.

Wide Temperature Range

The Flir One Pro allows you to measure temperatures up to 400°C (752°F). Quite simply, that is a top-notch performance from a thermal imaging camera designed for smartphones. The thermal sensor comes with a pixel size of 12 µm. The result is superior thermal imaging.

In most cases, you will not be using the high-temperature mode that stretches the limit to 752°F. That will be reserved for professionals like firefighters. Still, the broad thermal range makes it an extremely versatile device for a variety of purposes. Basically, it is perfect for both DIY projects and basic professional work.

The standard-mode comes with a temperature limit of 248°F. It will be sufficient for checking hot water pipes and electrical circuits. On the lower end, you can go below freezing to -20°C (-4°F).

Affordable Pricing

At one time, thermal imaging cameras are too expensive. Not any more. With the advancement in technology, the prices have come down. The Flir One Pro raises the bar higher by providing a higher thermal resolution at a reasonable price. Quite simply, the price to performance ratio works in its favor.

It offers features like the ability to check the temperature anywhere within the image frame. That makes it more versatile than devices with a center-spot-only meter. Simply drag your finger anywhere within the frame to check the temperature of that spot.

Also, imaging options are simple and effective. Interestingly, the contours from the visual image are superimposed on the thermal image to clearly identify the objects. In addition, there are plenty of color palettes to choose from. Apart from the standard orange-and-purple palette, you can also use the grayscale palette. 

Overall, it is a feature-rich product that offers real value.

Things to Know About the Flir One Pro

Here are some of the advanced features of the camera that you need to note.

Top-notch Accuracy

The Flir One Pro offers an accuracy of ±3°C or ±5%. The best accuracy levels are when the screen is between 5°C to 120°C. We checked some of the temperatures with the reading from a thermometer. Obviously, the distance and surface texture affected the camera accuracy levels. While the readings were not as precise as that from a thermometer, they were accurate enough.

Compatibility and Ease of Use

Now, the camera is available in three different variants-  for iOS devices, Micro USB Android devices, and USB-C Android devices. So you will find it compatible with almost all modern smartphones. Keep in mind that it is compatible only from iPhone 5 onwards.

Beyond that, you can capture images in JPEG format and videos in  MPEG-4 (MP4) format. Additionally, there is also a mode for capturing time-lapse videos. You can save the images along with any modifications in the JPEG format. That makes it super easy to share the images for analysis and reports.

The Flir App

We found the software is simple and responsive. You can easily adjust color palette, emissivity, turn the MSX feature on and off, and adjust temperature ranges. The Tips And Tricks section offers some cool ideas that first-time users will find helpful. There is also a Community tab that helps you connect with social media accounts related to Flir.

But hold on. That is not all.

Some of the long term users we contacted for this Flir One Pro review reported issues with the iOS app. These include long camera freeze and problems with the battery indicator. If these issues are fixed, the device will offer even more value.

Battery life:

The FLIR One Gen 3 is powered by its rechargeable lithium-ion battery, which is good for one-hour use. It charges with a usual micro-USB charger and can fully refuel in about 40 minutes.

Flir One runs from its battery and doesn’t filter the ones on your device. When idle, FLIR automatically switches to low power mode to increase battery life. The fully charged battery worked for several days without recharging.


The Lightning connection is reversible, so iOS users can plug the device into a forward or backward facing device depending on what you need to see.

The emission of both models is adjustable for calculating an object’s infrared emission – especially important for accurately measuring temperature. FLIR ONE offers even greater flexibility by providing an adjustable position and spacing through the updated app.

This helps expand the variation of the color palette (there are many of them) to the areas that are most concerned.

The third-generation FLIR ONE is the best design innovation for an adjustable connector. And the thumbscrew is permitting any device with or without a link to go in or out of the connection plug. Future applications of the same device do not require adjustment, and the connector will retain this setting.

The advanced FLIR One will also let the camera be switched from front to back in iOS (Lightning), Android (USB-C) configurations and Android (MICRO-USB).

Flir One Pro vs Flir One

Now, some of you might be wondering about the differences between the Flir One and the Flir One Pro. The fact is, there are a few significant differences between the two. 

Firstly, the One pro comes with a superior thermal sensor combined with the advanced VividIR™ image processing technology. That provides better image quality and makes it more suitable for professional use.

Secondly, the dynamic thermal range of the Flir One Pro is also higher(-20°C – 400°C). For the Flir One, it is (-20°C- 120°C). Another significant camera feature in the One Pro is the addition of multiple spot meters. Also, the One Pro can survive a drop of 1.8-meter compared to the 1.5-meter of the Flir One.

Considering all these advanced features, the extra cost of the Flir One Pro is justified.

FLIR ONE Pro – Android (USB-C)
  • FLIR ONE PRO: Powerful Infrared camera mobile accessary with adjustable one fit connector lets you find hidden electrical problems, energy loss, water damage, and other heat related issues.
  • IMAGE DETAIL & CLARITY: Record crisp 19,200 pixel IR images – a 4X improvement over the FLIR ONE Pro LT – at a thermal sensitivity of 70 mK.
  • EXPANDED MEASUREMENT: Measure temperatures up to 400 C – compared to a maximum of 120 C for the FLIR ONE Pro LT – with up to three spot temperature meters and six temperature regions of interest.
  • VIVIDIR IMAGE PROCESSING: Unique image processing technology that enhances resolution and accuracy, to help you catch potential problems early and reliably diagnose problems. When combined with MSX...
  • ONEFIT CONNECTOR: Adjustable connector extends by up to 4 mm, so you can secure your FLIR ONE Pro to your mobile device while its still in the protective case.
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03/10/2023 12:10 am GMT

FAQs for the Flir One Pro

Can I use this camera to detect fever?

The Flir One Pro can provide a fairly accurate reading for skin temperature. However, experts say that these devices do not provide an accurate reading for the body temperature like that of a medical thermometer.

Will the Flir One Pro drain my smartphone batteries?

The device comes with an internal battery that needs separate charging. So it will not drain the battery of your smartphone.

What is the visual range of the Flir One Pro?

The device can detect the thermal signature of a person from a distance of 40 m (130 ft.). However, apart from the lens quality and the pixel count, the performance will also depend on environmental conditions. Also, the temperature of the object and the background affects the results.

Will this camera work in foggy conditions?

Actually, the minute water droplets in fog cause scattering of light. This can adversely affect the performance of a thermal imaging camera. However, since this device comes without any IP rating, we advise that you do not use it in foggy or rainy conditions.

Final Words on Our Flir One Pro Review

Time to sum it up this Flir One Pro Gen 3 review.

Honestly, it is a solid performer in this price bracket. Even though it is a consumer-level device, the high image resolution and wide temperature range give it an edge over the other competitors. Besides, the rugged built quality makes it ideal for outdoor adventures.

While professionals who need the best may need to look elsewhere, occasional users will find it a practical choice for home improvement projects. Admittedly, it has a few drawbacks. But even taking those into account, it offers great value.

If you want to add thermal imaging capability to your smartphone, you will not go wrong with this compact device. Now, the choice is yours. 

About Kim Goodwin

Kim Goodwin holds a Master's in thermal engineering from the University of Rhode Island. At Thermo Gears, she reviews most equipment that uses thermal imaging technologies.

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