I have a Pentax *ist D. I am perfectly happy with the camera body, but would like to upgrade my lenses. I have an SMC Pentax-DA, 1:3.5-5.6, 18/55mm AL that came with it. It also came with a Quantaray 70-300mm 1:4-5.6 LD. I have been pretty content with these lenses but would like to improve the quality. Am I on the right track?