I've been reading that one way to get night landscapes, fireworks or what have you, that are more than roughly 100 feet away, you can simply focus your lens too infinity and it should be in focus. I've tried this, and have failed miserably... Two problems I see. One, with my cheaper lenses, I don't have that nifty little window telling me where my focus is. So, is there a rule of thumb for knowing when I'm at infinity? Such as, "if you're standing behind the camera, always turn the focusing ring...." Two, am I way off on my reading comprehension and should I use some other trick for focusing at night?