We can use the numpad keys to constrain the Viewport Camera to specific orientations when viewing the current scene. Numpad 1 is the front view, Numpad 3 is a side view, and Numpad 7 is the top view. I recently became interested in getting a very specific view of the scene, and to do it, I needed to use some of the other numpad keys. After using a complex combination of Numpad 2 and Numpad 8 to tilt the view along one axis, and the Numpad 4 and Numpad 6 keys to tilt the view along another, the next step was to get my render camera oriented to the same view as the Viewport Camera, so that I could render this newly acquired view. No issues there. After hitting CTRL + Alt + Numpad 0 I was able to render the scene. The next step was to continue from where I left off, and further adjust the scene's view, moving it further in the same direction using the already relied upon numpad keys. That is where I ran into a curious and unexpected problem. Apparently, this can't be done, possibly due to some kind of a loss of UI focus. Once the Render Camera is selected, which it must be before it can be oriented to the same view as the Viewport Camera, it is no longer possible to make adjustments to the Viewport Camera using the Numpad 2, Numpad 8, numpad 4 and numpad 6 keys. That is, UNTIL one FIRST presses either the Numpad 1, Numpad 3 or Numpad 7 keys. This, of course, means that the meticulously adjusted view previously achieved is lost as the Viewport Camera snaps back to one of these more standard orientations. And that is not what I want. What I want is a way to continue from the existing Viewport Camera orientation as a basis for making further view angle refinements, with a way to take render snapshots along the way. But moving and selecting the Render camera makes use of the "non-standard" numpad shortcuts impossible afterwards.
What is the solution to this problem?