Gorilla's breakfast answering "how sharp is it?"

I have been using the Sony 70-200mm f/2.8 GM II for almost two months now, and I’ve mentioned that it’s sharp even wide open. I’ve been asked a few times “how sharp is it?”. Today I thought I’d show you an answer. OK, two answers…

Just as I arrived at Werribee Open Range Zoo, one of the gorillas picked up a branch for breakfast, and I grabbed a couple of shots . This was in bright summer sunshine (zero cloud cover) and shot at 200mm f/2.8 1/4000 ISO 500. Could have been ISO 100, but that was legacy of shooting in shade earlier (doesn’t make a huge difference, because ISO 500 is the second base ISO on the A1). The bright sun even picks up flecks of dust in the air - that’s the sun still being fairly low in the sky when I took the shot.

The image above is a crop from the centre of the frame, and it’s a savage crop because he was a fair distance away. I cropped the full 8640 x 5760 frame all the way down to 2500 x 1875, and the cropped image is shown at 100% in the gallery below, together with a scaled version of the full frame. The cropped version shows the details of the fur on his head. Do you think this answers the question, at least for the centre of the lens? And yes, this was with the lens wide open.

Before I posted this, I showed the images to someone who didn’t like my example, and disputed the sharpness of the crop. Humph! OK, so I added another image, shot a few minutes later on the same day. This time it’s a lioness absorbing the sunshine (cats are solar-powered, after all). I photographed her at 200mm f/2.8 1/10000 ISO 500 (I really appreciate the A1’s ability to shoot up to 1/32000). The A1 eye AF nailed focus on her eye, too. This image is cropped just as savagely as the first one. Do you think that’s a good answer?