Thanks, Xterra. All those WA shots are done at ISO400 F8 with shutter around 1/250 - 1/500, handheld. Some fill flash will make it better but I'm too lazy I guess.
Checking EXIF data of these shots, I found most of these are shot at 35 mm focal length. This is a focal length I used least. I'm impressed with the sharpness at F8/close focusing distance. Will use it more. Probably try sticking the lens in front of people's nose and see what I can get.