Originally posted by Kunzite Yes:
Bring proof or be quiet. Speculating that a Pentax lens "might" be anything else than a Pentax lens, while having nothing to indicate this, is bashing.
Or at least damaging for the brand, because it fuels the ill intended individuals (and "rumor" sites) everywhere.
I took it as a lens size comparison and "proof" that the 21 Limited could be f/2 or so with that size.
I would bet on it being very similar to the 28-105 at 28mm, even the new roadmap posted in
Lens Roadmap 2020 June - PentaxForums.com shows both being roughly the same length but the barrel of the 21 is wider at the front (probably with a 67mm thread?).
Obviously the optical construction won't have anything to do with any of the others.