The grubby, high-ISO 1080i video above can't transmit this experience -- all we could do is zoom in on a detail and then zoom out again to show how small a proportion it was of the total image. Instead, it's better to just come out and say it: while watching the swimming event and cut-down highlights of the opening ceremony, there were moments when we could almost have believed we were looking not at a projected image, but rather through a window direct onto the Olympic Stadium or Aquatics Center itself.
Unlike HDTV and even 4K, there wasn't even the merest hint of pixelation or compression in the 500Mb/s IP feed, and even the tiniest figures in the scene were totally vivid and sharp; and, with 60 progressive frames per second of clean digital footage, there were none of flickers, artefacts or low-frame rate issues that come with trying to replicate 'reality' on 35mm celluloid. The sound was a big part of it too -- with an inordinate number of channels to position sound in the theater, it was impossible to tell whether the people sitting behind us were clapping or if it was actually someone in the Aquatics Center. Embarrassingly, there were a couple of occasions when we applauded an athlete and then realized we were the only ones in the theater making a sound. That's honestly how engaged we were.
However, these feelings never lasted long, because the shot would switch to another camera position which had worse contrast, or greater lens distortion, or shallower depth of field, and the illusion would be broken. In particular, there were occasions when what we wanted to focus on jarred with what the cameraman actually focused on -- because the vista was often so wide and detailed that it seemed we could choose any subject we wanted, and there was no need for cutaways. Wide shots worked best, when everything was visible and in focus. That said, many of these issues can be overcome, even if it means directors and cameramen have to work differently when broadcasting in 8K.
Ultimately, there's plenty of reason to believe the BBC's project head, Tim Plyming, when he says that "8K is the maximum the human eye can understand" and that "it's the end of the resolution story." As far as he's concerned, anyone investing in 4K may as well go right to the end of the track and put their money in 8K instead, because that's the technology that "puts people at the event."
As a broadcaster peering into the future, the BBC recognizes two very separate trends. The first, of course, is towards mobile, in which people increasingly want their video to be sent to phones and tablets as part of a data-rich stream of content. The second trend is towards immersion, in which people seek premium experiences on huge TVs and in theaters, and they want nothing to get in the way of their escapism: that's why the Olympic footage we saw had no commentary and no info-rich graphical overlays -- nothing except what a person at the event would see or hear. Plyming didn't state it specificially, but if you take this view to its logical conclusion, a regular 42-inch HDTV would get pushed into a no man's land somewhere inbetween -- it's not portable, not immersive, and therefore not able to compete in the long-term. And that's why broadcasters' investment in 8K perhaps isn't so wild after all.