I’ve enjoyed seeing Avatar – most recently at a very late night showing at the BFI Imax cinema. It’s not brilliantly plotted or scripted, but a great spectacle nonetheless.

However, I found myself focusing on a problem that 3D cinema has compounded – especially in the immersive environment of Imax. Because the screen is so large, and the 3D presentation gives the impression of depth, the temptation is to actually ‘look around’ the scene, rather than simply focus on the lead element in the shot. Trouble is, you can’t do this. There’s a fundamental depth of field problem when shooting through any lens: only one thing can be in focus at any one time.

I’m not really sure if there is any technological solution to this. But it struck me as an interesting limitation. No matter how immersive the experience, life through a lens has limited depth. The ability to change focus quickly, to draw in close and reach out wide, and for people to do this differently in the same vista, is uniquely real life.