Me again. As per 15,000 other threads, I have a Nikon D40 with the 18-55 and 55-200 lens. I've definitely been persuaded by many a very lovely MacRumors chap/chapess that an 18-200 lens would make life sweet, no more frantically changing from one lens to the other. The Nikon 18-200 lens is a little beyond my budget right now, so I've been looking at the Sigmas. This is where I'm hopelessly confused.....do any of the Sigma 18-200 lens auto focus with the D40? I'm getting wildly conflicting advice on this. No say most, but then there's this update. What do you think about the Sigma 18-200 for the D40 - good idea or not? Thanks.