Animate the depth of an object in camera space.
I have also found use for it to clean spacings in camera space as the baked tx and ty curves correspond to x and y spacing in the camera view.
It works best by selecting one controller as the target. The tool supports multi-controller selections by calculating the mid point of the controllers.
If you see the bake is not working well, there is a right click option called "layers". This option will make the bake a bit slower but it should be accurate.
Ckeck out the tool's video tutorial
Copy the script file into your maya scripts directory, for example:
C:\Users\YourUser\Documents\maya\scripts\emi_closerToCamera.py
Run the tool in a python shell or shelf button by importing the module, and then calling the primary function:
import emi_closerToCamera
emi_closerToCamera.ui()