Actually , I have several of these .....I think I am going for the " learn" option .....hell I'm a renovation carpenter , it's what I do....fix stuff! Time to expand the horizons! Thank you gentlemen~My guess is a loose lens but we'd all be guessing without it in our hands and likely having it apart. Even then, it may or may not be obvious. If your goal is to learn, take it apart. If your goal is a good scope, send it in or replace it.