Canon EF 70-200mm f/2.8L IS USM Autofocus Lens "sensitive subjects" Questions

what is this lense best suited for can it be used for macro as well as farther away images Like all Quantaray lenses, this lens is a very cheaply built model and so lacks the refinements, build ...

...shutter speed to the next faster value 1/60 sec. If you change the ISO to 400, it is now 4x's sensitive than 100 (or 2x's than 200). At ISO 400, you could go two f stops smaller to f 5.6 or ...