Lately Sigma had quite a run in delivering very decent products not only in terms of value but also optical & mechanical quality as well as improved quality control. The transformation of their product lineup is still at the beginning but they are busy executing their new product vision. One of their latest products in the Sigma 24-105mm f/4 HSM DG OS | A. As the name implies it is part of the "Art" series thus their most prestigious segment of lenses. In Canon land, it is obviously targeting the (rathe Canon EF 24-105mm f/4 USM L IS which has been the 1st choice among customers looking for a high quality, full format standard zoom lenses with a slightly longer reach. Interestingly the Sigma lens is just marginally more affordable than its Canon counterpart. This trend certainly shows that Sigma is getting more confident about its products compared to high end products from original manufacturers.