On the side of the phone there is an up/down switch which controls volume etc. In camera mode it allows a certain amount of exposure adjustment. To me this looks like white balance being changed here, rather than an apature/exposure time adjustment. Shots are in black and white mode so the colours don't distract from the exposure.

The image exposed at 'normal' setting is posted here, these four range from max white (top) to min white (bottom)