Shooting in 4K has recently become fashionable but it can be costly and impractical in post, writes Adrian Pennington.
As high-definition tapeless acquisition begins to impact on grass roots work from news to factual entertainment, digital capture up to four times the resolution of HD is beginning to filter through to the top end of the broadcast chain.
A handful of producers are experimenting with data cameras for drama, commercials and promos but there are questions marks over the true costs and benefits of acquiring at such high resolutions for broadcast.
There are a bewildering variety of such cameras a producer might turn to instead of film. These range from the Dalsa Origin, which lays claim to being the first camera capable of 4K capture to the Arri D-20 (currently used to shoot BBC Charles Dickens adaptation Little Dorrit).
Others include Thomson's Viper Filmstream, Silicon Imaging's SI-2K (its MINI version is popular for stereo 3D recording), the Panavision Genesis, Vision Research's Phantom (for high resolution slow motion) and the Sony F35 which ships in September.
Many of these mimic 35mm film depth of field by using single 35mm sized sensors as opposed to the 2/3-inch CCDs of video HD. Most provide the option of recording to tape or direct to hard disc.
Arri recently introduced the Arri D21 which, unlike its predecessor outputs raw uncompressed data to disc recorders such as the Codex.
The reason though that the broadcast community is buzzing about digital cinematography is Red, the Californian developer which has had the pertinence to take on Japanese camera giants like Sony at their own game.
At the beginning of the year (and after lengthy delays) it shipped Red One, a $18,000 4K camera aimed at the replacement of 35mm for feature film and drama.
In April it announced not only a successor called Epic which captures at even higher resolutions but a portable version dubbed Scarlet which for just U$3000 records 3K onto two CompactFlash cards.
Putting that into perspective, the professional broadcast standard HD cameras capture the equivalent of 2K resolution and cost around $80,000. Some other digital cinematography cameras cost double that.
"If Red delivers on its promise, these cameras have the potential to make a huge impact in independent production which has struggled to afford the cost of entry into quality HD," reports Daniel Sassen, Chief Engineer at leading London broadcast post producer Envy.
There are however many dissenting voices about the Red One's claims - mainly about that fact that after being processed by the camera's codec the workable output is somewhat less than the promised 4K resolution.
There are also complaints about the proprietary nature of its codec although details have now been released to third party manufacturers so this problem should ease.
Because of its low cost, the Red One is enticing producers to experiment with high-end capture for the first time. But there are pitfalls. Producers are advised b to shoot at the maximum resolution possible in order to preserve detail, shooting at resolutions above HD can actually deliver too much information.
"Even if the output is HD the 4K image contains so much detail that you need to take some information out of the image [pre-filtering] before it can be compressed into HD," explains Derek Clarke, Creative Director, Prime Focus London.
DP Anthony Dod Mantle and director Philip Martin made the decision to use the camera over 35mm for budgetary reasons.
"The bottom line is the quality of the image," says Dod Mantle. "Given that I'm working against the clock with a small crew I can get away with less on set and achieve more with further manipulation of the image in post. I can get enough quality with my minimal lighting but magnify it more significantly because there is much more definition, resolution and luminance."
The drama is being graded at Swedish facility Chimney Pot and finished at Soho's The Farm.
"The problem with handling such a huge amount of data for a broadcast output is at what point do we rescale the files to HD?" asks The Farm Technical Director David Klafkowski. "You don't want to risk losing important image information by downscaling but at some point you have to so you need to store the original 4k data in case you need to go back to it."
He adds, "Processing data ultimately takes as much time and cost as telecineing rushes. The problem is simply removed from the lab and into the post house. Consequently facilities must set up data management and answer questions like how many copies do we keep? Where are those copies? And which is deemed the master?"
Most productions will downsize straight away on ingest to 2K or 1080p HD for their post pipeline. The extra resolution makes a big difference at the camera stage, but can become an unnecessary complication afterwards.
"The sheer size of the images complicates the process," says Vincent Maza, Avid Market Manager for Post Production. "Facilities will need to invest in larger, faster storage systems that can preserve their workflow."
4K will present a genuine challenge for facilities simply because the infrastructure lags way behind. Currently there are very few 4K projectors and monitors around let alone realtime 4K colour graders.
"If you want to use and maintain a data path all the way through then the workflow changes considerably. Productions need to understand the new pressure points of such a decision," explains Shane Warden, co-MD of drama specialist facility Pepper. "What do you do with your data on location? How do you secure it and change it for the offline? How easy is it to create DVD and other viewing media for Executives during production and post?"
The debate over whether digital imaging is superior to film remains hotly-contested. Certain digital cameras can have the edge over film in terms of their ability to capture detail in low light but many cinematographers argue that 35mm and even 16mm perform far better in daylight or for capturing explosions.
"If the output is HD then the advantage of shooting at higher resolutions comes from the greater colour depth allowing the picture to be pushed a little further in the grade," explains Clarke. "4K is also good for vfx-intensive projects since in 4K you can extract detail for tracking or reframing, resolve composites or key in backgrounds and still finish with a great image."
Other arguments for shooting 4K will be familiar to those who pioneered HD.
"Shooting 4K, produce a 2K version now and store it as 4K data to future-proof your rushes," explains Adrian Bull, CTO, Ascent142.
"The biggest mistake people make with high-resolution cameras is to treat it like a video camera. They don't realise that you need a proper camera team to operate it including a DP, focus puller and someone to look after the data."
DP Gavin Finney used the tape-based Arri D20 to shoot Sky One dramas, Terry Pratchett's Hogfather and The Colour of Magic: "The problem with electronic equipment is that it relies on new software which is being beta tested in the market. That's fine for word processing but it's not OK when you're shooting on a big budget. The kit needs to be reliable before it's used and currently that's not always the case."
With the growth of solid state recording and a more IT focused workflow what we will increasingly require from manufacturers is adherence to international standards for metadata and codecs.
Jon Attard the BBC's Technology Controller would like to see is on-board options for codecs and formats so a camera works much more like a laptop with a lens on it.
"For instance if I wanted the ergonomics of camera X, recording medium A, but with codec Y I should be able to select it in that combination to meet my particular needs as a content producer," says Attard.
"Clearly this isn't going to happen overnight but as an aiming point for the camera manufacturing industry we'd really support this direction."
Sooner or later digital technology will exceed the colour depth and resolution of film.
"Why bother with developing, telecine, 2K scans - when you can take the files straight out of the camera and start editing?" asks Jon Wright, workflow consultant for facility 4K London. "By 2012 it's conceivable that shooting on film will be the exception rather than the rule. There's no question that cameras like the Red One will impact indie film production and higher end TV drama - shoots that might have previously gone with HDCAM or 16mm."
"A DIT is crucial to production and will have a high level of expertise," explains Paul Carter, MD, Axis Films. "They have sole responsibility for the safe storage and archiving of data."
The DIT takes care of metadata for use in post, spots and corrects issues with corrupt files and helps set the camera and monitors up according to how the DP wants the project to look.
"Digital imaging is in a bit of a 'wild west' state," says Carter. "The DITs role varies from project to project. On some projects they may take more of hand in colour management. There are no hard and fast rules."
DIT is now a professional grade recognised by unions in the US but that has not so far happened in Europe.
According to DP Gavin Finney, "DITs should act as a bridge between a second AC and a video assistant. It's certainly useful to have an engineer to monitor the electronics and check you've saved what you think you've saved, not least because with each new digital camera format the amount a camera crew has to learn goes up exponentially. My concern though is who is training them - since currently anyone can walk up and claim to be a DIT."