Zoom in the Camera Boom with a pressed button

Here’s an example of zooming in and out when holding the right click mouse button, when holding you zoom in softly, and when you release it you zoom back softly, my Spring arm length is 300, the MinLengh=100 and MaxLength=300 go ahead and try it out and let me know if you need help with a specific example.
You could do this in a timer if you want.
Increase Interp speed to speed things up a bit.