Get same image regardless of studio window-size?

The problem
I have a tool/model in workspace.
I want to take exactly the same image nomatter how high resolution I use on my screen.
But when you decrease the height of your studio window, the whole image shrinks.

The broken 'solution’
To compensate for this I tried to adjust FOV to cover for this loss:

CurrentCamera.FieldOfView = 50/710 * windowHeight
50 being the FOV at 710px resolution (height), aka default view (this is how all images should render regardless of windowsize).

It resulted in a close to similar image altho some parts are stretched out more than others

The orange backline is the 355px image placed behind the default (710px) image.

I realize to fix this I’d have to adjust the distance from my camera to the object.
I don’t know how tho…

Hope I explained the issue clearly, got any ideas?