Believe it or not every photo I have here has been taken with an iPhone of some sort. Right now I have the 6s Plus, and I found a great app called 645 Pro that hijacks the phones hardware and gives me control over everything except the aperture which is fixed. The app also allows the images to be stored RAW as TIFF files without ever being compressed. Hopefully soon I will invest in an actual camera but I've done a LOT of learning with just the phones over the last four years.