I have horrible eyes and 5 arken scopes. I have 2 sh4 4-16s, 1 Ep4 4-24, and 1 ep5. I have had no problems with these 4 scopes. I have been able to set parallax and focus on them as easily as I have on any of my high end scopes. However, I have been struggling with my sh4 24 power scope and can't seem to get it in focus. I just can't seem to get a clear view on it if I'm shooting over 50 yards. It seems like I have to readjust the diopter every time I switch distances. I know I have really bad eyes (5 power contact lenses) but it seems strange that this is the only Arken I've had issues with. Then again it's the only one I have of this model in 6-24 so I don'thave another one to compare it to.. Has anyone else who is seriously nearsighted had this issue with this scope? ...or did I get a bad one.