Red digital cinema camera

Pro-class digital movie cameras rely on ICs for market advantage

Why a new generation of professional-class digital cameras have caused legacy incumbents like Panavision to take stock of their core technology and re-focus their futures.

In June 2013 investment firm Wilmington Trust threatened to take control of one of movie-making's iconic equipment suppliers – the film camera rental company Panavision – over a seemingly small unpaid debt owed to the bank Credit Suisse. It was one indication of the way in which Panavision's influence over the movie-making business has slowly, but decidedly, waned over the past 10 years.

Although the 60-year-old company's financial problems started more than a decade ago, debt is not, arguably, Panavision's core challenge. Like Kodak in the photography market, Panavision has suffered from a mass migration towards new breeds of digital rather than film cameras. It means directors of photography are no longer taking up the familiar pose of squinting through the viewfinder of a Panavision camera, but instead gaze at a distance on an iPad-mini-sized LCD screen.

In 1995, nine out of the top ten movies hired Panavision's cameras. By 2013 the number among live-action movies shot on Panavision kit had fallen to four – and one of those used film cameras made by Arri which Panavision also rents out. The rest were predominantly shot on high-end professional digital cameras made by competitors, including longstanding movie supplier Arri and the upstart vendor Red.

Cinematographers on 'Thor: The Dark World' even used single-lens reflex (SLR) cameras designed by Canon – EOS 5D Mark IIs – for still-image photography, but which are also able to record video, as part of its shooting stock. It was far from being the first time for SLRs. For 2012's 'The Avengers', director Joss Whedon settled on an array of light, highly-portable SLRs to shoot many different perspectives at once.

As a highly successful incumbent, Panavision did not ignore the advent of the digital revolution by any means. The company developed some of the first purpose-designed digital movie cameras to be used in big-screen blockbusters such as the 'Star Wars' prequels. However, it was wrong-footed not just by a new generation of 'passionate' developers who have found ways to reuse technology developed for far less artistic applications, but by top-rank filmmakers moving over to devices primarily developed to capture still images.

The company is now attempting to recapture its position with a more advanced camera than those being touted by the upstarts which have been adopted by some of movies' biggest directorial and cinematographically-renown names, notably Peter Jackson, director of 'The Lord of the Rings' blockbusting series and 'The Hobbit'.

Sensory perceptions

The driver has been the rapid development of increasingly complex image sensors. The quest has been to obtain the sharpness and dynamic range of film, characteristics that led to the development of today's 4K cinema displays. When Kodak developed its Cineon film-scanning system in 1993, the company's engineers decided that the resolution needed to fully capture images recorded by film emulsion was 4096 x 2160 pixels for each of the three primary colours: demanding more than 25 million individual pixels.

This led to the specification for the 4K projection systems. Even now, the resolution of cameras falls some way short of 4K's demands, largely because of the trade-offs in sensor design and manufacturing, even though a number of cameras such as the Red Epic still sport the '4K' tag.

It did not take long for the first '4K' cameras to appear, although they did not meet with instant success. More than a decade ago, medical-imaging specialist Dalsa built a camera designed for 4K systems and showed it at the 2003 NAB (National Association of Broadcasters) conference in the US, although it was not made available for rental to third-parties for another three years. Dalsa's Origin camera could not just capture images with a resolution of 4096 x 2048, but it generated 14bit-per-pixel of data, providing higher dynamic range than most sensors of the time, which were topping out around 12bit.

Traditional chemical photographic technology excelled in its ability to capture the extreme scope of light intensity in the world around us. Whereas still-picture photographers will often exploit a low dynamic range to create silhouettes against a bright background, or bring a subject out of a dark background, filmmakers want the ability to have moving images that more or less mirror the outside world – albeit often heavily tweaked for effect. That means being able to place figures against a sunset and still have the audience be able to see their faces.

High-quality film stock is sensitive enough to record 14 stops, which translates to a dynamic range of more than 80dB – however, this is someway short of the human eye's ability to discern shadow detail on a bright day, which translates to a dynamic range of 100dB. A typical LCD-based screen has a dynamic range of around nine stops and Panavision's Genesis digital camera recorded with 11 stops of dynamic range.

The initial version of Dalsa's sensor could achieve a dynamic range of 72dB, according to the paper presented at the International Solid State Circuits Conference in early 2003, which was later pushed to 78dB, or around 13 stops.

To achieve its high performance, particularly in terms of dynamic range, Dalsa's 8MP sensor required a die measuring 600mm2. Its horizontal measurement was the same width as standard Super-35 film, including the sprocket holes. This provided an image size almost 150 per cent bigger than the 25mm-wide frame of a standard 35mm film frame, allowing for comparatively large areas for individual pixels. This, in turn, translated into lower noise, better dynamic range, and the ability to shoot in lower light levels.

The same approach was used for the 'full frame' sensor used in Canon's 1DS digital SLR, launched in 2002. This measured almost 36mm across and provided a resolution of 11MP, but was limited to still images. It would take several years before video-capable SLR designs appeared with similar sensors. The ability to use larger pixels to capture light from dim scenes contributed to the use of SLRs in movie-making. However, these are now being pushed aside by dedicated video-capture devices such as the Red Epic and Arri Alexa, which actually use physically smaller sensors.

Many of the popular movie-oriented cameras, including the Alexa and the Red Epic range, use a sensor size much closer to that of the Super-35 film image frame – 25 x 14mm. This reduces the amount of space used per pixel and, with it, light sensitivity, but helps reduce cost. In chipmaking, smaller die sizes generally result in higher yield as well as more chips per wafer – both contribute to a lower-cost product overall.

Top-grossing cameras

The Alexa and Epic featured prominently in 2013's top grossing movies. For example, Peter Jackson selected the Red for 'The Hobbit' trilogy. The Alexa played a major role in the filming of director Alfonso Cuarón's recent science-fiction/techno-thriller flick 'Gravity', accompanied by a custom-built LED-based lighting rig.

The Dalsa design did not fare so well. Like Panavision, Dalsa rented the camera out to production companies – for around $3,000 a day – rather than selling models outright like the Red. Despite its impressive performance for the time, the Origin and its successor were not a commercial success, and the company shuttered the movie camera in 2008. Despite this, the cameras were actually used in 2010 to shoot close-ups of objects that would suddenly grow in size in Tim Burton's adaptation of 'Alice in Wonderland'.

For its fight-back, Panavision has chosen the path of superior technology, such as Dalsa, to beat the challengers, asking movie directors to consider a contentious question: what makes a true 4K camera?

Panavision engineers such as John Galt argue that, up to now, there has in fact been no true 4K camera. The horizontal resolution of approximately 4,000 to 5,000 pixels in existing cameras needs to be shared among the three primary colours, whereas the projection systems provide that resolution for each colour.

A fully-comparable camera would need many more photosites than those available on conventional digital movie cameras, Galt and colleagues claimed in a paper for the Society of Motion Picture and Television Engineers' Motion Imaging Journal.

Although it might be possible to squeeze 25 million photosites into a sensor the size of a Super-35 frame, the sites would be a third smaller than the size Panavision's chip foundry could guarantee. "We also felt that [the] photosite pitch would have an unacceptably low dynamic range," the engineers said.

Why lenses loom large

However, the problems of manufacture took a back-seat to considerations of the lens optics. The resolution of current image sensors are already pushing the optical characteristics of 35mm film lenses.

Like colleagues in the still camera business, to build a practical camera with a 25 million pixel sensor, they would have to move up a size. Panavision turned to one of its old cameras designs, the 1959 Super Panavision 70, used to film the multi-Oscar winner 'Lawrence of Arabia' (directed by David Lean), a feature first released in 1962, and recently restored to be shown on 4K projection systems.

The larger lenses developed for the camera provide greater resolving power, which should fit the new sensor better. Although often regarded as the mainstream movie that demonstrated the creative impact that 70mm image capture and presentation was capable of, 'Lawrence of Arabia' was actually one of only 12 productions that used the state-of-the-art technology during its halcyon period of the 1960s: others included 'My Fair Lady' (1964) and '2001: A Space Odessey' (1968).

The Panavision 'digital 70mm' design arguably does not quite match the 4K projection systems. It still employs Bayer filtering – but it has many more photo sensors than 2014's cameras. Production cameras deploy just under 25 million photosites on a sensor that measures almost 50mm across – giving it an area three times larger than a Super-35 frame – to deliver a resolution of 3840 x 1620 for each of the three colours.

Like the Dalsa Origin and Red One cameras before it, news of the Panavision 70mm camera has greatly preceded its availability. Although the company claims the improved resolution will ease some of the digital processing tasks that are used to combine images in post-production, it is not altogether clear how much rental cost will factor into its success, or failure.

Dalsa arguably overestimated Hollywood's appetite for technology versus cost and portability, but lacked the longstanding connections that Panavision has with the movie business. The success of the digital format has demonstrated how much film-makers will risk on new entrants to the market.

As long as the camera brings something that gets them closer or beats the quality of film emulsion, directors will use advanced, high-end cameras if the shot needs it, as seen in 'Alice In Wonderland' or 'Quantum of Solace', if not for the bulk of the movie.

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