How do I calculate Field of View and camera position from 2 images?

I am trying to re-construct the camera logic of RE4 that is applied when the player aims a gun.

I have attached a hack to RE4 which enables the user to change the camera’s FOV. Because of that I already know that the FOV for aiming with a gun is 50. The FOV during normal gameplay is 75.

I have then taken 2 screenshots:

  • Screenshot #1 shows normal / idle gameplay
  • Screenshot #2 shows aiming gun gameplay

These are the 2 screenshots. The red frame indicates the area that is still visible when the player aims. As one can see, the left side is heavily cropped while the right side is not cropped at all. This makes me wonder what the logic is here.

I have tried to replicate this behaviour, but I don’t manage to make my scene look exactely like that.

I would therefore like to ask if there is perhaps a mathematical approach that I can use to calculate the camera position offset that is being applied when the player aims his gun.

Thank you!

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