"Moonlight, 08 July 2014. Canon 5D Mk III, 16-35/4 L IS at 16mm, f/4 at 1/3 second hand-held at ISO 12,800.
Hand-held at 1/3 of a second and sharp in the corners wide open! This is shot at LV -1.5, which means super dark.
The old 16-35/2.8 L II isn't this sharp in the corners at f/4, and it has no IS for sharp shots this slow hand-held. With the 16-35/2.8 L II you'd have to use a tripod, with which then you'd shoot at f/2.8 at 30 seconds at ISO 100 — but wait, at f/2.8 the old 16-35/2.8 L II isn't sharp, so to use the exposure you'd really want, f/11 at ISO 100, you'd need a remote release and an 8-minute exposure! "
Regardless of the other differences, is he seriously comparing shutter speeds with one shot at ISO 12,800 and the other at ISO 100? I'm not quite sure the point is. Yes, the 16-35mm is sharper at F4 and has IS, but this seems like exaggeration.