Initially I bought my dslr and sigma 18-200 (ver II) for an overseas trip. For the usage on that trip the 18-200 was a fairly good lense as I could vary from wider angle landscape shots, to closer shots of animals and wildlife.
However after shooting with my sigma 30mm, I'm find the drop in image quality from a travel zoom a lot more noticeable now and am wanting something sharper. (here are some of samples from the 18-200: https://photography-on-the.net …/showthread.php?t=1191661 ) I've been trying to use the 30mm prime only, but I do miss the versatility of zoom (mainly at the wider end)
I'd like another general zoom, and am tossing up between the canon 17-55 or 15-85. I tend to shoot people at family events and weddings. I enjoy shooting landscape. Generally not into shooting animals that much.
I'm thinking the 15-85mm will make a good alternative travel zoom and am willing to forgoe the 85-200mm, if I'm not shooting animals. If so I will sell the 18-200mm.
I like the fixed aperture and f2.8 of the 17-55. I feel like I might be missing out too much on the longer focal lengths and would most likely keep the 18-200 for travel.
So to summarise, here are some of the options I am thinking;
1. sell the 18-200, get the 15-85mm. Will have more $$$ for other things since the 15-85mm is cheaper and I sell the other lens
2. get the 17-55, keep the 18-200 in case I need the longer focal lengths
3. I'd like to eventually go full frame and am very tempted by the nikon d600. Just keep using what I've got - save money for full frame and suitable lenses.