Fixing my zoom / camera angles

So i have tried my hand at this zoom for my ADS system and i have it working on the initial zoom in. But for the life of me i cannot get it to zoom back out on the button release. I have been racking my brain on this one for several days now. Any assistance would be truly appreciated. While i am on the subject of zooming. Can this process also be used to zoom the camera out a bit when the player is sprinting. I was thinking i could probably use this set up. I also seen the mention of a lerp as well but i am awfully new to UE4 and not familiar without to use it. I know I am asking a bit much. One more Thing, I would like my camera to be different for Melee (combat mode) / Gun (combat mode) / and unequipped. Any tutorials and pointers are welcome.