By the way, I did end up buying one of those Sigma 24-70 zoom lenses in the end. I got a reasonable amount of change left over from a hundred pounds, whereas the equivelent Nikkor version would have left me with a few pennies out of half a grand.
The lens is very plasticy, but seems to be built moderately well. I wouldn't want to try dropping it though. (By comparison, my longer Nikkor-Q lens could probably double as a police baton and still take photos afterwards.) The sigma lense is technically designed for an autofocus system, as almost all recently manufactured lenses are. The manual focus operation is consistent with most AF lenses in manual mode - ie. Annoying. The range of travel from infinity to minimum is about, ooh, maybe 35 degrees at most, perhaps less? It is quite loose, too, like the aperture setting.
This is only likely to be of annoyance to people who still use manual modes, like me.
There is a depth of field graph on the casing, but due to the small range of motion, the lines are so close together as to be useless. My camera has a depth of field preview button, which I tend to prefer anyway, so I'm not too bothered by that.
I wandered around London on Saturday while the sun was out, and took a bunch of photos with this lens. Once I became used to the minute range of the focus wheel, I was able to focus accurately, fairly quickly, and it was nice to have the ability to switch between wide-angle and telephoto shots quickly. I don't intend for this to replace my prime lenses, but for when I don't want to carry around several kilograms of glass, it's certainly handy.
I'm quite interested to see how the negatives come out, compared to using the Nikkor glass. Is anyone interested in a quick blind test later this month? ;)
