Apple iPhone iOS 7.1 - Manual (Page 81)

Chapter 12 Camera 81
Camera settings
Go to Settings > Photos & Camera for camera options, which include:
•
photo streams
•
slideshow
•
grid
Adjust the volume of the shutter sound with the Ringer and Alerts settings in Settings > Sounds.
Or mute the sound using the Ring/Silent switch. (In some countries, muting is disabled.)