i had to check just yesterday because somebody else asked the same question.
i'll have to check up at 18x tomorrow, but at 3.6 mine is good to ~25 yards
That's why you can adjust the parallax knob. Mine was at about 300 when it was focused at 100. Loosened the screws and spun it, everything lines up great now.
My 5-25 will do about 50, but it's not a good .22 scope. I could shoot it close on 5x, but it's just out of it's element there.