iPhone: You have a lot of great options for photo apps on the iPhone, but if you're looking for something with expert controls, Manual is one of the most customisable camera apps we've seen. It allows you to fiddle around with just about every camera setting you can imagine.
You can adjust white balance, exposure, focus, ISO and shutter speed. Essentially, you can adjust all the settings you'd expect to adjust on real camera. All the options can get a bit confusing for an amateur, but if you're used to shooting with a DSLR, Manual makes the iPhone more fun to use. You'll need iOS 8 to use it.
Manual ($2.49) [iTunes App Store]