I've just downloaded the Red Dot Camera app from iTunes. It simulates a manual focus "rangefinder" by using touch-screen dials for shutter speed, ISO, EV compensation, and focus There is no auto-focus or zoom, but a choice of three fixed focal lengths; nor is there aperture control, due to the small size of the lens.
As an iPhone 5 user, this is more intuitive and less cumbersome than the device's own camera.
It's free with an imprint on images or you pay for the full version.
Colin.