Infrared camera on mobile phone – great infrared photos (with any smartphone)

Infrared photography has been an interesting niche for many decades. IR photographers first used special film to enjoy their hobby, and in the digital age, they took apart their DSLRs, often with shaky hands, to remove the sensor’s infrared filter. And now, for the first time, there’s also an infrared camera out of the box on smartphones, namely the OnePlus 8 Pro.

Contents:

1. Infrared camera: how does it work?
2. Exciting photo motifs for infrared photos
3. Why can I see through plastic?
4. Take infrared photos with any smartphone

Let’s start with a bit of technical information: How does the OnePlus 8 Pro’s infrared camera actually work? A conventional 2-megapixel image sensor of the most economical design takes care of infrared photos. But what is different here?

Foveon & Co. aside, the individual pixels of each image sensor always only measure brightness and thus deliver black-and-white photos. To make the images colourful, manufacturers give the sensors a so-called Bayer mask, in which a color filter is placed over each pixel and alternately transforms the pixels into red, green or blue light sensors. From the color information of surrounding pixels of different colors, the image processing in the mobile phone interpolates an RGB value for the individual pixels.

With an infrared sensor you can save this Bayer mask. Instead of the color filter array, there is simply a filter for visible light on top of the sensor, which only lets through low-frequency infrared light. Et voilà: You have a monochrome infrared sensor. Because the pixels of the image sensors also respond to infrared light by default. You can read further down in the article how you can use this fact to take infrared photos with any smartphone.

So why are thousands of photographers now risking the warranty and lifespan of their DSLRs to turn it into an IR-capable full-spectrum camera? Very simple: the world looks completely different with infrared eyes. The photos take on a dreamlike look that can hardly be reproduced even with software filters.

Plants, for example, become extremely bright and appear almost white in sunlight on infrared photos. This is because the plant pigment, chlorophyll, reflects not only green wavelengths, but also light in the near-infrared range. Lots of reflection means: lots of light, and that makes plants look white.

The sky, on the other hand, looks very dark or even black during the day, which gives a great contrast to any vegetation. This is because the clear sky simply does not reflect or emit infrared light. Clouds, on the other hand, are different: they reflect infrared light very strongly and thus form a great contrast to the black sky. This means that sunny days with prominent cumulus clouds are particularly suitable for infrared photography.

We tested it ourselves: with the OnePlus 8 Pro’s photochromic camera you can see through all sorts of things, like “X-ray glasses for the poor” (even if X-rays, of course, affect completely different frequency ranges) . Why is that?

Very simple: if a company produces something that is not supposed to be transparent, it uses visible light as a guide. Whether a given material is transparent to infrared light or not is a purely random property due to this priority. And so it happens that some (thin) fabrics and a number of plastics let infrared light through. And this is exactly what you can see with the photochromic mode of the OnePlus 8 Pro.

The hype about “nude scanners on cell phones” was now too big for OnePlus itself. The manufacturer has already announced a software update that will disable the infrared camera, at least indoors. The meaning? Questionable. The update has not yet reached our OnePlus 8 Pro.

If you don’t have a OnePlus 8 Pro or want to have open heart surgery on your DSLR, you can take infrared photos with many other smartphones or cameras. Because many cameras respond not only to visible light, but also, at least to a limited extent, to infrared light. You can easily test if this is the case with your smartphone. Open the camera app, point an infrared remote at the lens, and press a few buttons. If you see the infrared LED light up, the image sensor also responds to infrared light.

Now you “only” have to block visible light. You can find countless filters for this in specialty stores or on the Internet. It is always important to specify the wavelength from which the respective model filters the light. If the threshold is too low, you will get too much visible light in the photo. If the threshold is too high, the image remains black. In any case, you have to get used to manual mode, longer exposure times, tripod and recording in RAW mode.

For more details on how to edit the resulting infrared photos, I recommend this brilliant article by Vlad Moldovean at Petapixel. As you can see in the photo above, we also ordered a bunch of infrared filters and achieved very impressive results with the OnePlus 8 Pro’s standard camera.

Are you interested in infrared photography with your smartphone?

conclusion

We’ve published a number of smartphone photography know-how articles over the past few weeks, and I’ve happily rant a lot about unnecessary features and marketing gibberish. What do you say: Photochrome mode falls into the “hack” category for you? Or can you imagine using the feature regularly?

For me, infrared photography and the OnePlus 8 Pro are definitely a small “reminder” of the wonderful world we live in, and of which we can only perceive a small fraction.

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