Andy Ho said:My Nikkor 17-55mm is pretty sharp at f/2.8 at all focal length from 17mm through to 55mm. That much I can tell you after shooting various events at wide open apertures because the lighting is so nice I thought I prefer to do available light than let the flash spoil everything. Of cause I do use flash most of the times but a photographer has to be decisive to know when to use flash and when not to.
When closed down to f/5.6 or f/8 the lens is perfectly tack sharp. The only time my lens is not sharp is because the camera back focuses on the subject.
is the lens focusing fast enough under low light?