touch input speed to camera rotate speed. scaling function needed

I have a camera attached to the head of my player and i use touch inputs to control where the player looks. The problem is that i want to scale the movement of the players look depending on the speed of the swipe. for example a slow swipe should move the players head slowly and give more precision on where to look and a fast swipe should move the players look direction quickly so they can react to the world quickly.

The current solution i have is to look for a threshold value on the input and scale this vlaue but i would prefer a method that does not work on a threshold value. but works on some kind of scaling function but i cannot find an answer that reacts correctly, ether te function is too quick or too slow. what is a common solution to this problem?

My current solution

 void OnDragging(DragInfo dragInfo)
     {
             if(dragInfo.delta.magnitude * Time.deltaTime < 1.1f )
             {
                 dragDelta = (dragInfo.delta / 4.0f); //Vector2.Lerp(dragDelta, dragInfo.delta / 4.0f, Time.deltaTime * 100f);
             }
             else
             {
                 dragDelta = dragInfo.delta;
             }
     }