on Kern Switar 25mmF/1.4 C-mount
Hood's opening is Ø49mm, a kind of too large for
Pentax-Qs, but pretty good with µ4/3 cameras,
and also you can use 49mm lens cap as a hood cap.

If you need a hood for this lens, find Ø32mm hood,
Tiffen Series #4 is the one. It is hard to find thou.