Already Animated Camera in my scene, Camera view changes when switched to 1080 in render settings

[Jim Scott]

I’m not quite sure what you mean by “re-render with the new view,” so what I think you are hoping to do is avoid re-animating your camera but still have an output with your new render settings which mimics your original view.

If, for example, you switched from a standard aspect ratio (4:3) to a wide screen aspect ratio (16:9) it will result in the “zoom in” that you experienced. To avoid redoing your camera animation you could try reducing the camera’s focal length in its Object settings to give a view which is similar to your original. Since altering the aspect ratio changes the shape of the view seen by the camera it’s impossible to get it to look exactly the same as your original, but you can effectively zoom back out and regain space around the objects in the scene by changing the focal length.

Unless you stay with the same aspect ratio (and only increase the resolution for the final render) you will be altering the look of your scene. It’s a good habit to decide initially what your final output will be and then stick with that throughout, or at least work from that same aspect ratio, but at a lower resolution, to speed up test renders.

I hope I understood your question correctly.

[Steve Bentley]

Something else to watch out for:
Any attribute of the camera you haven’t got keyframes for will change permanently if you accidentally move the camera. I’m forever zooming in with the viewport controls on my camera view port and screwing up hours of intricate camera moves. And for me, undo has never worked where it comes to the camera.
So if you have keyframed x and y but not the z position or any of the headings, and you adjust that camera’s veiwport, you are stuck with a new version of what you animated. No amount of pounding on the undo button will help ( I know, I’ve tried!)