Originally Posted by
Benjamin
Relax my friend. It is normal for any IS DSLR lens to make the buzzing sound. That's just how the IS unit work. It also comes with two clicks when the IS turns on and off. You can also check out at a local camera store with different IS lenses, they're all the same, no matter Canon or Nikon or whatever. That way you'll be convinced.
I had the 70-200/4L IS for almost two years now. However, if you find that the image in your viewfinder shakes at the moment when the IS is turning on, that might be a problem. But the sound is just normal.
Ben
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