For a given lens and given film or sensor format, this simulator shows how much it is possible a front raise and where the horizon line will end up in the final picture. Focusing is assumed to be at, or closer to, infinity, a frequently used condition for a landscape.
1 – The scheme is presented up side down in order to keep the perception that the sky rests above and ground below the horizon line. It is not considered, in this way, that lens image is actually reversed, I preferred to show this way a more intuitive simulation.
2 – Lens movement is supposed to keep its axis horizontal and perpendicular to picture plane. That is the condition on which vertical lines in the scene are kept vertical, like those of buildings, in the final image.
3 – Swapping width and height, the same thinking can be applied to lateral movements