Flir Infrared Camera E4

I always wanted an infrared camera, but it wasn’t until recently that the prices came down enough for hobbyist usage. Admittedly, $995 is still high enough that only semi-professional shops, labs, and home energy inspectors will use it enough to honestly justify the expense.

The FLIR E4 is a well-built, easy-to-use, highly-capable portable camera with both infrared and visible-light imaging. The display is absolutely gorgeous.

Flir E4 thermal imaging camera

Flir E4 thermal imaging camera

Positives include:

Weaknesses are:

The last five limitations can be overcome if you’re willing to customize your device. Nevertheless, this is a great device that I’m very satisfied with!


The first thing everyone does with a thermal imaging device is take pictures of the people around them. My wife didn’t give me grief about buying an unnecessary-but-awesome tech toy, so she gets the honor of being shown first. James drank a glass of water to darken his mouth in his shot.

Rachel has a cold nose (infrared) James Cook after a cool drink (infrared)

Rachel has a cold nose and James has a cold mouth (infrared)

Notice that the thermal image makes it seem like James is wearing dark sunglasses. Although the glass frames are cooler because they are away from his face, the plain glass lenses are not transparent to infrared wavelengths -- and thus appear dark. As you can see below, you can get a nice ’selfie' off the reflection of glass windows, instead of being able to see through them.

Infrared selfie in window reflection

Infrared selfie in window reflection

Remember this when you are inspecting a spooky basement or darkened room. If you suddenly see a figure quietly approaching, it is not a ghost, it is your reflection. (Not that I scared myself multiple times, of course.)

Speaking of the basement, the next most stereotypical thermal image that everyone seems obligated to snap is the electrical panel. The difference in temperatures for various circuit breakers is due to the amount of electrical load drawn on those circuits.

Circuit breaker panel infrared< Circuit breaker panel visible

Circuit breaker panel (infrared and visible)

Power loss and heating can be serious issues with heavy-duty appliances and home mechanicals. The high-current demand of a sump pump can be seen in thermal images of the power cord. The heat generated in the cable represents wasted energy and lower motor performance.

Sump pump electrical cable infrared Sump pump electrical cable visible

Sump pump electrical cable (infrared and visible)

Fortunately the pump itself appears to be staying cool because it is submerged in water.

Sump pump infrared Sump pump visible

Submerged sump pump (infrared and visible)

Going outside, another classic shot is a thermal image of a car. This demonstrates the heating of the wheels due to the mechanical brakes.

Automobile infrared Automobile visible

Automobile (infrared and visible)

Vegetation converts sunlight into stored energy and has an organic water cooling system. Therefore, plants tend to stay much cooler than thermally-insulative inanimate objects such as rocks and pavement, as demonstrated in this image of a raised bed.

Strawberry plant bed infrared Strawberry plant bed visible

Strawberry plant bed (infrared and visible)

Those strawberries aren’t ready yet, so dinner needs to get cooked.

Charcoal grill infrared Charcoal grill visible

Charcoal grill (infrared and visible)

The temperature of the fire exceeds the maximum range on the Flir E4. That’s why you see “>536” on the hot crosshair value.

What do I have that will exceed the minimum range? At night, if you aim straight up, what temperature is the sky?

Night sky infrared Night sky cloudy infrared

Night sky clear and cloudy (infrared)

For an extreme difference, take a thermal image of the sun and the clear sky together. (Warning: concentrated sunlight through the lens may damage the sensor.)

Sun and sky infrared Sun and sky visible

Sun and sky infrared (infrared and visible)

Speaking of concentrated sunlight, how hot is the bright spot generated by a magnifying glass outside? Hot enough to solder electronics and ignite sticks.

Magnifying glass burning stick infrared Magnifying glass burning stick visible

Magnifying glass burning stick (infrared and visible)

Let’s continue exploring the infrared world on the next page.