So, I want to make decision about buying a telephoto lens, the Canon EF-S 55-250mm f/4-5.6 IS STM and Canon EF 75-300mm f/4-5.6 III USM. Which annoys me is the IS function, my friends asked me "what are you photographing?" then I said, I would like to use the tele for outdoors and sport (with high-shutter speed of course), but within the shutter 1/200, my hands still shaky or something. How much benefit will using IS give over not using it at all, in general?