According to reports by American website 9to5Mac, the new iPhone5S will be equipped with a dual-LED flash module. French website NEW leaked pictures of the phone's rear shell which shows a slot large enough to hold two LEDs.
KGI Securities analyst Ming Chi-Kuo explains that the LED flash will contain both white and yellow-based lights allowing for more natural indoor pictures.
Different types of light have different color temperatures. Daylight has the color temperature of about 5500K-6500K, while indoor lighting tends to have a color temperature of 3000K. The lower the temperature, the more yellow in hue the light is. In order to offset the yellow tone, cameras will adjust the white balance which leads to problems when the flash is employed. For indoor shots, pictures will come out with people looking whiter while the background has a more yellow tinge. So, if the iPhone5S uses yellow lights for flash indoors, then the color temperature of the picture will be more balanced giving the user a more natural looking photo.
However, it is important to note that leaked pictures of the components should be met with skepticism since most are of third-party components or fakes. That being said, it is already rumored that the iPhone5S will come with duel-LED flash.