As others have said, it depends on the lens, as well as the camera (SLR/RF, etc.), your own breath control and steadiness or lack thereof, etc., etc. I have used monopods for many years, and with an SLR and normal (or close to) lens, I can shoot down to 1/15 easily, 1/8 or even longer with good breath control and something to lean against. I'm shooting dance performances now in dark theaters with an 80-200 f2.8 on a monopod at 1/125, but will sometimes go as low as 1/60 if needed. Any lower and subject motion will be too great an issue.