Some iPhone 4 owners have reported colour oddities with photos they’ve taken with the camera on the back of the newly released phone. The iPhone’s 5-megapixel camera will take crisp daylight and brightly lit indoor photos that show colours accurately, but then have issues correctly capturing images in low light with, or without, the LED flash.
Images shot with these iPhones in warm, indoor lighting without the flash, have an obvious yellow and sometimes green cast to them. The exact same photo taken with an iPhone 3GS or 3G will not. You can see for yourself in the image below - the photo shot by the iPhone appears in the upper right corner, while the 3G and 3GS images are on the left. (We also included a photo shot by a Canon 5D digital camera for the sake of comparison.)
Apple hasn’t confirmed what’s causing the issue - in fact, the company has yet to respond to our email asking about the issue. But it appears possible that this is an issue with the camera’s auto-white balance.
Because different types of light shine with a different colour, a digital camera needs to calibrate to the type of light it's shooting in. This is called white balancing, and it’s necessary to get accurate colour in a photograph. For example, sunlight, fluorescent light, candle light, tungsten bulbs, electronic flash and LED flash, each create a unique hue in photographs.
Without proper white balance settings, images shot in bright sunlight will have a cool blue look, and photos lit by tungsten light bulbs will be warm and yellow. The iPhone 4 doesn’t seem to choose the proper white balance settings when taking photos in warmer lighting, creating yellow images that can’t be easily fixed with a photo editor.
Many of the iPhone 4 users who are experiencing this yellowing problem are also seeing yellow-green flesh tones when using the LED flash in similar low-light situations. The combination of the LED’s cool blue light with the warm interior lights gives skin a sickly green appearance - one that could be also be fixed with proper white balance.
Unfortunately, fixing these JPEGs with iPhoto or even Photoshop isn’t always possible. I’ve had the most luck with the white balance settings in Lightroom 3, but that’s an advanced (and expensive) way to edit such a small photo.
Hopefully, this isn't a hardware issue involving the camera's lens, and Apple can fix the problem with an update to the iPhone 4's firmware. Currently, Apple’s Website doesn't offer any help document for the yellow images; Apple customer service has no official recommendation other than to let you exchange your iPhone 4 for a new one. That that would require a few days without the phone, or a $29 dollar charge for the replacement plan which puts a new iPhone in your hands before you mail the old one off. There is no guarantee that the replacement iPhone wouldn’t experience the same issues.