Seaside at Espergaerde

Zf  Voigtländer 28mm

APO f/2.0?

The start of a beautiful day - Z5ii & AF-S 300mm PF

Mighty mountains. Beautiful light

I would definitely not recommend shimming at the mount with tape.
You will change the alignment of the whole optical path. Not just one corner.

Agreed Erik that shimming is a kind of last resort action. One would prefer a perfectly aligned camera mount and lens.

But it is quite frequent that it is not the case and the purpose of shimming then is to restore, as much as possible, the optical path.

Non aligned mounts (either camera or lens) or unevenly screwed optical blocks in a lens result in misalignments equivalent to the Scheimpflug effect better explained here: https://en.wikipedia.org/wiki/Scheimpflug_principle. You could experiment with this effect by "free lensing" your lens out of the mount or when using tilt lenses.

True that slightly misaligned optical block (when the problem does not relate to the mounts) should be corrected at the level of that block itself to obtain a perfect optical path. But this requires skills and equipment far from the reach of an amateur and certainly far beyond what I could do.

So shimming is a tentative to average the corners of a lens, in relation to both mounts (camera, including adapter when there is one, and lens) and optical blocks imperfect positionning to obtain the best possible result to straighten the optical path in relation to the Scheimpflug effect.

It is a practical approach and I would not had engaged in it without benefits.

Hiding in plain sight

Blossom

Olympus E-500  40-150mm f/4-5.6  Zuiko