All hand held. The 600mm shots were at 1/40 - 1/250 s, which is on the slow side. An f/2.8 would have given extra edge.
Hmm, I think the slow shutter speed might be a big factor in that shot at 600mm, even with IS. If you want razor sharpness at the pixel level hand-held at 600mm, you ideally need over 1/1250, held very steady (say on a monopod) with IS switched off...in my opinion (at least on a stationary subject...on moving subjects it's always best to have IS on and in panning mode for every shot regardless of shutter speed). No I've not used this lens, but it's been true of all telephoto lenses I've owned or used. At 300mm, or especially shorter than that, you can easily achieve maximum sharpness at shutter speeds 1/250 and even slower hand held, with the IS on. But not at longer than 400, or especially 600mm. All IS systems, even the best ones, produce a bit of vibration that adds anywhere from a very subtle blur, to a noticeable one...when viewing at 100%. If viewing at 50%, then the effect can't be seen at all.