Sigma has released the 17-70mm T2.8-4. They are calling it the â€œUltimate Standard Lensâ€. I would beg to differ. There is nothing ultimate about the lens changing aperture cause of a little zoom action. Â The iris change makes this more like a T4 lens than a T2.8. Another limiting factor is that this is a DC or APS-C lens that does not cover full frame 35mm.
This lens does have some decent focus markings and image stabilization. A close focus of 8.7 inches throughout the entire zoom range and an inner focus system. Yet the iris changes. This makes the lens almost useless for video. When are lens companies going to figure out that we want to be able to lock in exposure at any focal range? Not screw around with ISO in the middle of the shot.