As a hobbist, my choice of photographic equipment is more based on value rather than absolute quality. There is usually a big jump in price for high end products. As I shoot with a DX format dslr with no plans to upgrade to full frame in the near future, my preference is for DX specific lenses at a much lower price point whenever possible. While the sharpest and highest build quality lenses are normally reserved for full frame, the DX versions can retail for as low as half the price.