I have a canon t3 with the 18-55 and 55-250 lenses. I've been looking for a 500mm lense and found an Opteka 500/1000 on Amazon. This is a 500mm lense with a 2x adapter. Has anyone had any experience with this lense? I'm definatly an amature so don't need and can't afford an expensive lense but would like one that will produce decent pics. Other suggestions would be helpful as long as it is in my price range.