Acquisition lIghting Grip Support and BVE Show Issue
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Cameras more for less? by Bob Pank T here is plenty of guidance available about how to shoot ‘good’ stereo 3D and the principles are quite easy to understand. Achieving good results takes good equipment and, maybe, the assistance of a stereographer and even a convergence puller... unless you are using one of those twin-lens cameras where most of the parameters are fixed – except for the convergence point. The big difference is that twin-lens cameras are 3D cameras whereas what most professional cameramen use is a pair of 2D cameras mounted and precisely aligned onto a 3D rig. This allows many degrees of freedom to get the 3D set-up exactly as you want, or to make a mess of it! Of course, the latter does not happen and part of the reason is that there are now excellent 3D test and measurement tools so that you can easily and quickly see if the alignment is as you want it. Cel-soft’s Cel-Scope3D enables analyses 3D video signals in dual-stream or multiplexed formats. It provides quick, easy stereoscopic camera alignment with disparities analysed and displayed as anaglyph on 2D or 3D monitors. It can also keep an eye out for edge and depth budget violations. For S3D colour correction Eyeheight’s new CC-3D does the job, allowing left and right channels to be corrected under common single control. Today’s twin-lens cameras have their limitations, such as a fixed interaxial distance that restricts their 3D use to close in, say up to 30 feet, shots. Typically, for longer shots, side-by- 44 | TV-BAY MAGAZINE side rigs are used to expand the interaxial distance and so ‘see’ the 3D on long zooms... although hopefully avoiding the cardboard cut-out effect. But then there’s another challenge. No two zoom lenses are exactly the same. It may be possible to synchronise their focal lengths but as the glass rotates the tiny lens-to-lens imperfections that didn’t matter in 2D show up and distort the 3D effect. The Sony MPE-200 3D Box can, with the right software and set-ups, track this and correct the images. All this technology and its operation come at a price. At the other end of the scale, studio work and close-ups are the sole realm of mirror (aka split beam) rigs. They tend to be more compact and they also have the advantage of allowing very small interaxial distances – much less than side-by-side rigs that are ultimately limited by the width of the camera bodies. Whilst on my compressed half-day version of the three-day 3D training course at Sony, I discovered that interaxial distances regularly go down to around 10mm for close-ups – way below our interocular distance of 63mm. This amazed me... but then the onward viewing system, cinema or TV, is very different to what humans have. Professional twin-lens shoulder-mount cameras are available, such as the Panasonic AG-3DA1 and the Sony PMW-TD300 (due in the UK April 2012). There is also a range of pro-am hand-held camcorders from the same manufacturers as well as JVC. The professional cameras have opened up possibilities for 3D news and some location applications, where there is no time to set up shots, no specialists to tweak the rig and only a 2D budget. Certainly these cameras, at about £20,000 in the UK, are far cheaper than a traditional 3D rig, and they score again as they have their built-in recorder – replacing the two needed with the rigs. The downside is that the picture quality is not likely to match the very high standards achieved on the rigs – which is often up to cinema standards. In time this type of camera could be serving the bulk of a much expanded 3D production world which, to date, has been small and mainly focussed on the top of the TV quality range, or for movies. And with everyone screaming for more 3D content, this has to be a move in the right direction. As with many new technologies, there is more to learn about 3D than you may have thought. Even the experts can get caught out. The subject of adding graphics to 3D pictures has been raised again, as highlighted by James Careless reporting in TV Technology on lessons learned at ESPN, >>