You want to create a '3rd' point that sits in between them.
Then 'push' this out along the arc of the distance between the two entities...then just position the camera there. it'll always be evenly distanced from the two entities as long as you 'lock' the camera to the 'vector' that the mid point is pushed out into.
Then 'push' this out along the arc of the distance between the two entities...then just position the camera there. it'll always be evenly distanced from the two entities as long as you 'lock' the camera to the 'vector' that the mid point is pushed out into.