Sharpness

Nikon AF-S 24-70 mm f/2.8G 28 mm @ center:	Nikon AF-S 24-70 mm f/2.8G 28 mm @ edge:
Nikon AF-S 28-70 mm f/2.8D 28 mm @ center:	Nikon AF-S 28-70 mm f/2.8D 28 mm @ edge:
f/2.8 f/4 f/5.6 f/8