Are you talking about a soft button release (also called a softy) screwed into the camera shutter button thread? If so, do you want to keep it in semi-permanently?
I have never done it, but would probably avoid using a thread-locker like Loctite blue (242) as it may be a bit overkill for the thread-size application. Also, as you unscrew it, the hardened solvent breaks up as a bluish-white powder - and small hardened particles - and it might get into places you don’t want. And also, you may break the threaded shaft of the softy (depending on its metal quality) while trying to overcome the breaking force of the thread-locker - leaving it stuck in the shutter button.
If you must, Loctite 222 is a less aggressive thread-locker and may be more appropos for this situation. It’s also good for eye-glass screws as is clear nail polish.
Purple, low-strength threadlocker for small fasteners
www.henkel-adhesives.com
I also used to use a product called “Vibta-Tite” and it makes the removal of a threaded application more serviceable. This may be a better choice. I like the glass bottle w/brush applicator, but the little tube should be way more than enough for many applications.
www.vibra-tite.com
I have used this stuff - and other adhesives - building medical devices (cardio/angio X-Ray Cath labs) for over a decade in my younger days.
Good luck.
