When vertical shift is used in camera settings, the camera frame can become offset from the viewport frame.
This is how vertical shift works in the real world with a camera, where the image is shifted away from the camera sensor.
That's cool for cameras in the real world.
In Max, since we're talking about software rather than the physical functions of a real camera and lens combo, and that the output of Max is used for compositing, it would be nice to have an option to keep the two frames aligned.
Why? Well why the heck not? If I can fake all kinds of other things in 3D and CGI, why won't you let me fake this?
It can make camera matching to images with bad perspective just a little easier to composite. Without it, the render needs to be repositioned on the background in post. If I could click a box and the two frames are aligned, the render will drop right on top of the background in the correct spot.
Maybe it's an edge-use case. I don't know.
