I hope the scenery is also clear at 100 yards and farther and maybe closer in to say 50 yards.
At 100 yards, the bulls eye is so small that you need a scope with some great magnification like 12 power or more to actually see the bulls eye. If you can see the place where you want to place your bullets to clear enough, you are doing great.
If however the scenery is not clear, but out of focus while viewing through scope, and you can see better with your own eyes, then you have to change the position of the front lens if it is indeed adjustable or move the rear eye piece slightly. Loosen lock ring if equipped. And turn one way or the other to see which way you get a better view.
Then do this. Point firearm and view through scope at normal eye relief distance at a blank wall or at a cloud or a patch or blue sky. Crosshairs should be in perfect focus.
If not, go see a gunsmith and have scope checked over and re adjusted. If your vision is at fault, get your vision corrected. Then use your scope.