Time Lapse FOV is Lower When Increasing Resolution

[AlexLandherr]

I recently tried increasing the camera resolution for my Raspberry Pi Camera V2 module in /boot/octopi.txt to camera_usb_options="-r 1920x1080 -f 10" from the previous camera_usb_options="-r 1280x720 -f 10".

The expectation was that it would work well (after adjusting the video bitrate to the maximum value allowable) it seemed to work well.
Then I noticed that the FOV seemed lower after going from 720p to 1080p despite not having adjusted the focus of the camera module.

The horizontal FOV was practically the same; the vertical was however not the same. I couldn't see as much of the hot-end of my Prusa Mini+ as before. I've included images below to show the difference.

Example frame from time lapse start when set to 1920x1080 pixels (note that only the tip of the extruder is visible):

Example frame from time lapse start when set to 1280x720 pixels (note that now much more of the hot-end is visible):

Now my understanding is that increasing the resolution used in this case would use a larger area of the image sensor thus widening the FOV to some degree; not narrow it. As stated above the focus on the camera module used has not been shifted nor has the camera mount point shown below shifted either:

Does anyone have a good idea as to why this is happening? Any help would be greatly appreciated.