Main Camera moving comparively to player weapon.

Hi, I am working on a melee FPS and currently have the players sword & shield attached to the Main Camera object.

However, the effect I want is that the main camera's movement is not completely relative to the weapons. For example, if you move the camera down by 20 degrees, it will also move down the weapon by, say, 5 degrees. That way the two are not intrinsically related, and it produces the effect that weapons are being held out infront of the player. How can I achieve this?