Battlefield 4 style sniper scope effect


So does somebody know a theory of Battlefield 4 style sniper scope effect? Like black sides and in the middle of the screen zoom and “crosshair”. I have Unity free, so it gives a few problems.


The main idea is to have a GUITexture with the black sides and crosshair that is off when starting. Place an empty game object at the end of the scope where the eye should be.

When you press to get to sniper mode, lerp the camera from normal position to eye scope position, enable the GUITexture and start playing with field of view, decreasing the angle will create a sniper mode.