AudioMedia - July 2008 - (Page 59)

video guide A Sound Pro’s Guide To Video HD Acquisition: Part 2 n e ws Digital cinema camera manufacturer Dalsa has named Sohonet Solutions as a preferred partner to supervise the distribution of material produced by its Origin and Evolution cameras in a production chain. Dalsa has already formed a working relationship with the service provider, which is the newly formed production services arm of media distribution specialist Sohonet. Under the arrangement, Sohonet Solutions will manage and deliver material from Dalsa cameras on set and location, ensuring it reaches the correct production department by the most efficient means. Jon Ferguy, Senior Partner at Sohonet Solutions, said that the company is able to carry the k output for Dalsa cameras in a quicker and more efficient way than workflows involving HD camera footage converted to tape. “This will mean that Dalsa users will benefit not just from the higher quality of the Dalsa images but substantial savings in time and resources, both on set and into post,” he said. Rob Hummel, President of digital cinema at Dalsa, commented, “I have worked with the Sohonet team since I was with Warner Bros., and at Dalsa we recently used Sohonet Solutions for a major effects shoot for the new Bond production [Quantum of Solace], and could not have completed that project without them. Not surprisingly, Sohonet again exceeded my expectations. We’re confident that any production using Sohonet Solutions will have a great experience.” With its extension eyepiece the Viper has a familiar shape and appearance, so it does not appear too out of place on set. At the back of the camera body are three BNC plugs, one for sending HD-SDI to conventional monitors, and two that handle the FilmStream feed. There is an optional output unit that has a fourth BNC connector to carry down-converted PAL. Three HD-DPM CCDs handle image processing and capture. These are designed to give the conventional HD image size of 1920 horizontal pixels by 1080 vertical pixels, creating a complete picture with 2073, 600 pixels, conforming to the world HD standard. But as the HD-DPM chip has four times the number of vertical subpixels, while maintaining 1920 in the horizontal, different groups can be assembled to produce a variety of visual effects, particularly in relation to aspect ratios. > would a film image. Another advantage is that a logarithmic picture has smaller changes in the density of the dark portions of images, compared to the lighter sections, which again is similar to how the brain processes this information. Thomson chose to make FilmStream a nonproprietary system, regarding it as “a very convenient way to transport real-time RGB-log, fullresolution picture data”. Other manufacturers and developers are able to use FilmStream, but as it is a registered trademark, Thomson’s ownership of the interface technology, and the name and logo, has to be acknowledged on any third party product or system. A technical condition is that the FilmStream log curve can be used only with dual-link HD-SDI and full resolution RGB (an approximation of 4:2:2 in YUV is prohibited). To provide a recording medium for the Viper, Arri Media, the first hire company in the UK to stock the camera, assembled eight hard disks in a relatively small but still unwieldy housing. This gave in the region of minutes of storage in full FilmStream mode, and approximately an hour if a HD-SDI feed was used. As data cannot be passed direct from the camera to the recording medium, a processing and monitoring unit known as the Director’s Friend was developed and became in the first portable hard disk HD-SDI recorder. This device also allows a A Small Snake House degree of image manipulation to be performed, although this does not affect the raw material and is recorded as separate metadata. Purpose-built hard disk video recorders are more common, compact, and affordable today, and include the Codex Digital unit, developed by Paul Bamborough, a founder of both SSL and Lightworks. Recording is on RAID arrays branded as the DiskPack; two of these provide approximately 54-minutes of 4k 24p material, while a single array gives 50 minutes in 1920x1080, 10-bit, RGB 4:4:4 form, also at 24p. Thomson produces its own solid state recorder for the Viper, which can be either docked on to the camera or linked using Bluetooth. The Grass Valley Venom FlashPak also works with the LDK 6000 Mk II WorldCam multi-format HD camera, and offers ten minutes of recording time in FilmStream mode, and 18 minutes in 4:2:2 HD format. This great capacity and ability to produce pure pictures that come close to 35mm film in the amount of data they contain was the big attraction of the Viper. It was also a considerable mark against the camera, because to get longer recording times it cannot be operated as a camcorder and has to be connected to a storage medium. This is less of a problem now, and the Viper has featured on a number of commercials and some major feature films. Its credits include part of monster movie Cloverfield, most of Collateral and Michael Mann’s return to Miami Vice. “This great capacity and ability to produce pure pictures that come close to 35mm film in the amount of data they contain was the big attraction of the Viper.” By grouping together every four vertical subpixels the conventional -line HD picture shape is produced. Arranging every three pixels in a group will result in resolution but as a cinemascope-style ratio of . : . Using every five pixels produces a : aspect (the widescreen familiar from digital television) with lines. This gives the Viper the edge over cameras with a static vertical pixel arrangement, particularly when working in the anamorphic format (see glossary), that gives only around vertical lines. Although CCDs feature an ‘electronic shutter’ that can turn off the pixels by converting photons into electrons, or doing away with the electrons altogether, they are continually responsive to light. Leaving the Viper’s chip array on at all times can produce blurring or streaking in the images. To avoid this, a mechanical shutter is fitted to the side of the camera and prevents light from hitting the CCDs for short passages in every frame sequence. During these periods, data is sent to a device that only plays out and is in constant darkness. This frees the image array for the next frame. Tak ing The Edge The Viper looks very much like modern mm film cameras, making it more acceptable to cinematographers. But I t Looks 'Normal' The Viper has been used with Zeiss and Panavision Prime (i.e., fixed) lenses, that most DoPs regard as the only opticals capable of getting the best into and out of HD/digital cameras. Arriflex accessories are compatible with the Viper, and the necessary support bars can be fitted to its body. The number of digital cinema cameras available to cinematographers is not vast, but then the 35mm camera market has never been oversubscribed as both are specialist items with only a limited demand for them. Next month’s Video Guide will look at the other contenders, the Panavision Genesis, the Dalsa Origin and Evolution, the Red , and the high-speed Weisscam HS- . ∫ S ocially Compatible AUDIO MEDIA JULY 2008 59

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AudioMedia - July 2008 Contents Recording Post Broadcast What's Up UK Geofocus: France For the Record Special Report: Develop Preview SE Electronics 4400 Sennheiser MKH800 Twin Tubetech Club Final Cut: Wanted Smart AV Tango Doctor Who Made in America DSP Roundup Product Sampler: Summer Hits Edirol R44 Video Guide AMSR Fame - Le Musical Waves MaxxBCL Yamaha AD8HR Special Supplement

AudioMedia - July 2008

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