Presence is a free iOS app.
It's optimized for iPhone 5, and needs iOS 6.1 or newer and works with iPhone, iPad and iPod Touch.
I downloaded the Presence app on an iPad Mini and set it as my "camera."
From there, you can make all sorts of custom adjustments, including the sensitivity of the motion sensors, whether or not the built-in flashlight is on or off for night vision, and more.
Then you can view live streaming on your second iOS device.
Presence is very similar to the Manything iOS app.
Although unlike Manything, it doesn't have its own IFTTT channel.
Presence does appear to have more direct product integrations, though.
It can work alongside Presence and Monster smart plugs, and TED and Blue Line PowerCost systems.
Presence also has its own "online store" where it sells stands and other third-party accessories.