SIGMA LENS 100-400/5-6.3 DG OS HSM CANON CONTEMPORARYAn ultra telephoto lens with an optical stabilizer (OS) system has several advantages. The OS allows the photographer to take photographs in unstable circumstances. The narrow angle of view makes it possible to dramatically compress perspective and flexible handling of the background. The photographer can thereby make the subject appear to jump out of the image, with the area in focus impressively sharp and clear. Nevertheless, ultra telephoto lenses