18-200mm focus problem (focus scale)
I'm wondering about this issue as well! I'm planning to get some photos of fireworks the next couple days. My plan is to use the tripod with ~ 8 second exposure at f8, manual focus at infinity.
While focusing on a distant object, I discovered my 18-200 won't AF to infinity at the 18mm end. Instead it focuses at 3 meters. At the 200mm end, it does seem to find infinity.
So where is infinity? I'll probably be shooting the fireworks more at the wide end and want to make sure I'm really in focus. I'm wondering if I should use a different lens?