Hard to explain, let's say that you have a nice camera set with a good point of view, but there is too much floor an a little bit of sky, so the lens offset will move the camera up or down without affecting the perspective.
Here is an example from Blender:
With lens offset:
As you can see the perspective or camera height hasn't change at all, only the lenses has gotten a offset.
all I think it does it to make the vertical edges actually look vertical in 3D.
Lens shift does the same thing. You level the camera so that lines are vertical then shift the image up or down to get the composition
The process in AC is different, but the end result is the same. You rotate the camera up or down for composition (which means the camera is not level and so the verticals converge) and then use the 2 point perspective to straighten the verticals
Moving the camera up or down (rather than rotating) to achieve the composition changes the viewpoint height, which is not desirable in most cases
I normally use what is already described here (look up a bit, then use 2 point perspective mode).
"lens shift" is the term in other software to mimic the behaviour of tilt-shift lenses commonly used in architectural photography, the same feature is available in Cinema 4D as "Film Offset" (both in X and Y directions).
the method available in AC is far from viably usable in my opinion, as you can't really control this numerically, you can just eyeball it (so comparing options is hard with the same tilt shift.
my suggestion is to use proper software that let you control compositions with a high degree of control, if you need it. I never do composition work or rendering with Archicad anymore, C4D and Corona is my go-to place. the same issues apply for Twinmotion/Enscape, I find they lack the necessary degree of control.
a solution could be to have the same camera as C4D does (which has this option linked to the camera object, not the view itself), but I don't think it's worth the effort and I wouldn't want to see resources wasted on this, when there are more pressing usability issues.
odv.hu | actively using: AC25-26 INT | Rhino7-WIP | macOS @ apple silicon / win10 x64
I normally use Blender to mkae the viz, export the model from AC to Blender, sadly in a teamwork project where everyone updates the model constantly they have decided to use enscape for this matter 🙄. Hence the need to try to use "advanced" camera settings inside AC.
Blender being a open source, would be awesome to be able to export the file in blend format natively.