With my contacts in (better than 20/20) - I have to get more than 10 feet away to get the effect.
With my old glasses, about -1.5 I only have to be 4-5 feet away.
Without glasses (I\'m -2.75) I get the effect at about 6-7 inches, weakly, and further out, the picture is too blurry to see. Goddamn I\'m blind