I personally don't use any lenses or anything like that, but right now I use the Halide app for iPhone almost primarily. It shoots in raw and extends beyond the stock camera app, while still keeping the layout simple for regular photo snapping. If I use the stock app, I usually go behind it with the VSCO app to further enhance the pictures. Do you guys have any favorites, or do you prefer to just use the regular stock app for photography? I do some amateur photography, so the extra benefits in a more advanced app are worth it for me.