Camera Extras is an add-on for your camera on a Nokia Lumia.
Along with the original application, Camera Extras adds a few more actions like:
Smart Group Shot - for group shots
Action Shot - for pictures in motion
Self-timer - countdown before taking a picture
Panorama - take large panoramic images
These add-ons expand the use of your device to bring the usage equal to other devices.
Camera Extras is an essential add-on.