Originally posted by Cvrn I now have a Sigma 70-300 and the 18-55 that came with the body as well as i bought a Sigma 50-500mm that I am wishing when I bought it i would have done a different lens though.
If you're having buyer's remorse over the Bigma, why don't you just sell it and pick up a higher quality wider-angle lens or 2 (upgrade your kit lens)? You've got some great choices out there like the DA 16-45/4, Sigma 17-70/2.8-4 macro, Sigma 18-50/2.8 macro, Tamron 28-75/2.8, Pentax *16-50/2.8 (if you can get a hold of a copy that doesn't have QC issues) in the way of zooms. There are also Pentax's excellent limited primes--the "pancakes": 21, 40, and 70mm, as well as the FA Ltd. primes: the 31, 43, and 77mm; in addition to the 50/1.4, they would make excellent low-light choices, as well.
If you've got the APO version of the Sigma 70-300, you should stick with that because for the price, the IQ is great and it has a macro feature, just in case you're interested in that. If you need longer than 300 on occasion, then you might want to consider getting a teleconverter.
Something else that you might consider getting is a book titled "Understanding Exposure" by Bryan Peterson. It's a great book that will help you develop your skills as a photographer and comes highly recommended by me and a lot of other people around here. Next month, he's coming out with another book titled "Understanding Shutter Speed", which I'm looking forward to getting my hands, on as well. He writes in an easy-to-understand style and uses a lot of great color pics as examples of what he's trying to explain.
HTH,
Heather