iPhone 5 Camera Does Purple Haze, But Isn't Alone!

Some iPhone 5 users have recently been reporting a problem with the phone's camera, which apparently adds purple halos to bright pats of pictures. Apple's response is that this is "normal behaviour" for the iPhone 5 camera, and, to be honest, they're not entirely wrong.


Users have been complaining in online forums (such as AnandTech) that photos taken with the new Apple iPhone 5 are prone to purple flare, especially when taken facing a strong light source. Like everything to do with the iPhone 5, the user (and sometimes non-user) response has started to swell, with various examples of the iPhone's purple haze posted on Internet forums and Twitter.

One Gizmodo reader was apparently told by Apple Support that: "Our engineering team just gave me this information and we recommend that you angle the camera away from the bright light source when taking pictures. The purple flare in the image provided is considered normal behavior for iPhone 5's camera."


So is this purple fringing as "normal" as Apple claims? Well, yes, actually. Almost all cameras can be affected to some extent by "purple fringes". Note that this isn't the same as chromatic aberration, which shows up as clearly delimited red and green fringes, and it's not the same as glare, where bright, white  zones are overexposed. Like "lens flare" (coloured rings, circles or starburst effects aligned diagonally in the image), purple fringing is caused by the reflection of unwanted, non-image-forming light inside the lens.

Logically, these reflections are more visible when there's lots of light—like when shooting into direct sunlight, with light coming in through a window, or with a strong light source falling directly on the lens (see right, part of a photo taken with the Canon SX230). These effects disappear progressively as you move away from the given light source.

Adapting the build of a lens or using special lens treatments/coatings can help reduce this effect. However, the restrictions that inevitably come with designing a smartphone camera (thickness, cost, durability of the front lens, etc.) probably don't give manufacturers the same room for manoeuvre as with a stand-alone camera. Pretty much all cameraphones therefore show signs of this effect to varying extents. It's only truly eliminated by avoiding situations where a strong light source is shining directly on the lens. A lens hood can be handy, then.

We didn't identify a particularly high sensitivity to light when testing the iPhone 5 camera—then again, the sun shining particularly strongly last week. However, user comparisons seem to show that the new iPhone 5 is a little more sensitive than the iPhone 4 and 4S. Some user photos show large and very visible purple zones (like the wall in the picture of the lamp).

But is that enough to justify a "purplegate" scandal, as some users are already calling this? Well, that would be taking things a bit too far. This kind of effect isn't abnormal—it was present in the previous models and is still seen in plenty of competitor handsets in some form or another.

Note that there are some software-based filters out there that can detect the unwanted purple zones in an image then correct the colours and adjust the contrast. They can't totally eliminate the problem but they drastically reduce its visibility. Apple's engineers could therefore potentially integrate such a function via an iOS update, which would no doubt be a better solution than telling users not to take pictures of sunny scenes.

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