Wednesday, 14 September 2016

iPhone 7 Plus and Bokeh

Bokeh. A week ago, you could have had a flu epidemic in most cities and stood a good chance than not one person sneezing would have known what the hell bokeh was. But Apple have come down from the mountain, in and among getting mixed up about the meaning of the word “courage”, and promised a phone camera which will deliver “bokeh”.

I have two things to say about that, and I don’t know which fist to punch the wall with first. 

Soddit. “Bokeh” first. Bokeh is the cool word for the way that the background blurs when you focus on a nearby subject with a long lens that’s been banged out to the maximum aperture. It used to be an inescapable nuisance of photography. The iron laws of optics mean that the closer you are to a subject, the less of it will be in focus. The bigger the negative, the worse the problem gets. Also, the more the lens magnifies the image, the worse the problem gets. It’s yet another of the annoying ways that cameras are just crap at a job which eyes do better.

Seriously, look up from the computer screen. Depending on your age, either everything was in focus immediately, or it was all in focus within a second or so. A camera can’t do that. Largely because a camera doesn’t have a brain behind it sorting everything out for you so that everything looks sharp and in focus at all times - in reality, about four per cent of what you’re seeing is a live feed of sharp imagery and the rest is your brain remembering what it looked like from a few seconds ago.

When there’s nothing you can do about a problem, you just have to make it into an opportunity, and so along comes bokeh. If the camera can’t keep everything in focus the same way an eye appears to, use the selective focus as a way to highlight the important part of the picture and blur out what doesn’t matter. The most common approach is in portraits; thirty years ago, if you got close enough to a person with a serious camera that their face filled the frame, everything behind them would be out of focus. Lemons, lemon soufflĂ©.

And here we are in the wonderful 21st century. The average phone camera can get a crisp well exposed shot in the kind of light which would have needed professional lighting thirty years ago, and no-one even realises what an improvement that is. And the shot is pretty much just like the way the eye sees it, with everything in focus. Finally, cameras can take pictures which look like what we see and remember of the moment.

Somehow, this is terrible news. Because there’s no bokeh any more. The iron laws of optics again. Phone cameras use wide angle lenses and a negative the size of a match-head. Everything is in focus because it can’t not be. The wider the lens angle and the smaller the negative, the more of the picture is in focus. Serious arty photographers are crying into their beer. Or carrying around eight pounds of kit so that they can choose which bit of the picture is in focus and properly exposed.

Apple heard all this crying, and stepped forward with a new kind of camera in their phone. Which will give everyone the chance to look arty. 

Yeah, it won’t. The new lens is a 56mm equivalent. Bokeh doesn’t start to get usefully apparent until you’re at 85mm and longer. And that’s on old school 35mm film. On a tiny cameraphone image sensor, there’s going to be no bokeh effect of any kind. Apple have pretty much conceded this - their bokeh effect will not be available at first until they can improve the software. And at that point, it’s not a photographic breakthrough; it’s a goddam instagram filter. And we already had those. 

What Apple is offering you is a chance to mess up your pictures so that they will look different to the way that the world actually looks when you see it yourself. If they really wanted to shake things up, they’d be pushing us to take advantage of a camera which actually sees the world properly.

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