Custom Cam allows you to fully control your iPhone’s camera.

You can switch between full manual mode, automatic shutter speed or ISO mode and full auto mode.
Custom Cam has a 3D Touch shutter button that emulates the half-press of traditional cameras.

The Best Professional iPhone Camera App Yet
-Sean Molin, Fstoppers.com

The app also features:
– Manual, auto and face detect focus
– A very intuitive swipe based system for changing the shutter speed, ISO, focus, white balance and exposure compensation.
– A light-meter, that anybody who has ever used a camera in manual mode will be familiar with.
– Two assignable buttons on screen.
– The option to save your photos as uncompressed TIFF files.

The 3D Touch shutter button allows you to lock focus and/or exposure with a half-press.
The half-press is achieved by touching the button, to take a picture simply press deeper.

You can set either of the on-screen buttons to be the 3D Touch shutter button, a focus lock button, an exposure lock button or a traditional shutter button.
Or just turn the second button off for a cleaner ui.

Changing the camera’s settings is done via a set of intuitive swipe gestures, which are very easy to learn.
For example: if your phone is in the landscape orientation, just swipe left or right across the screen on the half which contains the iso label to change the iso value.
A full explanation of all available gestures is found by pressing the in app help button.

There's currently a small bug that causes some of the smaller buttons and the manual white balance to become unresponsive.
The update to fix this has been submitted and will be available as soon as it's approved.

Custom Cam works on all iPhones running iOS 9 or higher.