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Title: large and heavy, fast and great optics
Review: Canon makes 4 L designated lenses in 70-200 range. The question often is f 2.8 vs f 4, and IS vs No IS. I found the image quality of this lens fantastic, wide open, even at 200mm. I find for me IS is essential for this focal length, as I am often shooting portraits with this lens at 1/60th to 1/100 of second. The f2.8 allows for a more accurate focusing as well as better lowlight focusing, and of course, one stop of light. The downsides is that its heavier and more expensive than the f4 variant, but I think well worth it.
