In praise of bokeh: the dilemmas of TV filming

Put on your shades and pull the high collar of your black robe high like Keanu Reeves in the Matrix - we are going to be talking about reality, and its depiction on film. Or on digital video to be precise. We are going to be talking about bokeh.

Bokeh is a Japanese term used by photographers to describe that pleasing effect where the background of a photo is defocused, often into blobs or hexagons, while the subject is razor sharp. It's what you need a real lens for, and it's produced by the effect of the little blades that open and close the aperture, letting the light onto the sensor.

If you're sharp-eyed you will notice bokeh has suddenly splattered onto your TV screen, as journalists have begun to use Digital SLR cameras to shoot video (trailing by about two years the practice of activists and demonstrators). Normal TV cameras, costing maybe five times as much as a Canon 5D MkII , don't really do Bokeh. They're designed to keep more of the scene in focus, and to maximize clarity over moodiness.

Now while documentary TV teams and arts programmes have been using SLR lenses for a couple of years now on TV, the startling thing has been its use by frontline cameramen in wars and revolutions, most notably in Libya and Syria by BBC cameramen and others.

In a series of three films I've just made for Newsnight in America, we decided to go Bokeh. My cameraman, Peter Murtaugh, used a Sony video camera called NEXFS100. Basically a square box that takes SLR lenses and can shoot very high quality video on a 35mm sensor (so every frame it takes has the same quality as a 35mm film shot).

We fitted it with Nikon SLR lenses - for camera nerds a 50mm f1.4 prime, the veteran 17-35mm wide zoom, keeping the Sony kit lens (18-200mm) for long shots. And we shot at 24 frames per second - the same as in celluloid feature films.

The most important change was: we didn't need lights. For anything. The 50mm prime, at f1.4, allows you to shoot interviews by candlelight, and captures a night-time demonstration well. Instantly relieved of carting a lighting kit around Manhattan, everybody in the team (producer, cameraman, reporter) became happier.

I should add here, that shooting this way has been pioneered by the producer on these films, Warwick Harrington, in his Peabody-award winning series White Horse Village.

Second - and this may be purely psychological, and may not last - we were able to run interview clips for longer because the picture, and the face, is more interesting. A head shot in an interview no longer felt like a dead shot.

You do miss the ability to zoom. For action we found ourselves increasingly having to switch to the Sony 200mm zoom lens, which is not as good as the others. However, what happens is you compensate by shooting action in a more photographic way - letting people and things move through a static shot.

And as all stills photographers know, shooting news with a wide zoom forces you to get inside the action.

A final operational change was, among the Occupy protesters, people tended to assume we were not a network news crew. Which is an advantage.

Now to the point raised by, among others, TV critic Charlie Brooker (read his article here): all this makes news look more filmic and can therefore be distorting reality. I have been fascinated and concerned by this ever since I saw the BBC and rival networks start using SLRs to shoot the Libya conflict.

The base case is, the SLR-shot video is tangibly different from the live studio shots that surround it, and from all other video output on the bulletin, and from the past. Therefore it is privileging the action, or giving it an extra narrative feel that distances us from the maybe horrific events.

Obviously some of these objections will go away over time, if all TV video gets shot in HD through shallow-depth lenses. But you will still be left with the contrast with the studio. And, for example, a football match will never - not soon anyway - be able to be shot like this (though all stills sport photography uses the same technique) - so "news" will feel different from other captured live reality.

However there is one bigger objection - millions of people now shoot actuality video themselves, on their Androids and iPhones. And the video here has the exact opposite quality to that shot on an SLR, or on a movie-style camera such as we used. It is grainy; it is "interlaced", so on every paused shot you will see blurring. The sound is tinny, the shot always wobbly etc.

So, taking stock, what's happening is that the potential sources of "news" footage are now four different technologies:

- the legacy cameras from the tape era which will always beat an SLR for long-range clarity but not rich colour, or bokeh

- iPhone footage with its unchallengeable "truth"

- SLR-shot footage, with or without a slower frame rate to make it look filmic

- live, static versions of the old TV cameras, with lighting etc in a studio or live satellite position.

- You could add, for increasingly cash strapped programmes that can't afford satellite feeds, Skype interviews.

- And while I think about it, there is also the GoPro, an ultra-wide, ultra-sharp mini camera people use to film themselves, ski-ing, surfing and taking their dog in their kayak etc.

There's suddenly a high diversity of image quality in news footage. I think the modern viewer is OK with this (I can remember picture editors "rejecting" early mobile footage on the grounds that it did not conform to broadcast standards).

But what it forces the video journalist to do is - where they are taking a positive choice - to justify why they're using a particular type of image, or shot. It also breaks up the profession, in the sense that 10 years ago, if a cameraperson and reporter arrived on a scene and the producer said shoot A, B and C, everybody would swing into action in the same way, even if they had never before met. Not true now.

Myself, I am in the mode described by Cole Porter in his famously double-entendre laden song: "Experiment". But even while experimenting you have to justify and assess your results.

Watch my Bokeh film on the car industry here, and for more Bokeh glory, watch Newsnight tonight at 10.30pm on BBC Two.

Watch Paul's full report on bokeh on Tuesday 1 May 2012 at 10.30pm on BBC Two, then afterwards on the BBC iPlayer and Newsnight website.