just ordered a lens for the nikon. it's a 70-210 f3.5 vivitar series 1 AI. i had read that there were five version, version one through three having exceptional optics and the latter two not so much. so, looking over my order i noticed that the one coming my way is 67mm which i now understand to be the first version. considering i only paid $17 i figure there's a piece to this puzzle that's missing. is this lens really a turd? if it is i'm fine with that, i wasn't expecting much for $17, and really it was an impulse buy. chime in if you have experience. thanks guys, you're the best.