Canon CJ20ex7.8B IASE S 브로셔
Lens Strategies for the Era of 4K UHD Digital Motion Imaging
Abstract
4K digital origination is today firmly entrenched in the world of theatrical motion picture production. The
Super 35mm image format size had reigned for the many decades of motion picture film production and it
became the pivotal format during the transition from film to digital – although it is not the only image
format size in use in the new digital motion imaging era.
Separately, digital 4K has been internationally standardized for television production under the banner of
UHD or 4K UHD – a consequence of the slightly different digital sampling format to that of cine 4K – and
it is already being used for some high end television production. Meanwhile, the Super 35mm image
format has become quite popular for many program genres in broadcast HDTV production that favor the
accompanying cinematic look.
It was probably inevitable that broadcasters would begin to explore the possibilities of 4K UHD for the
globally popular world of outside broadcast sports coverage; and indeed, recent years have seen a great
deal of related experimental projects. The 4K UHD lens issue soon surfaced as the limitations of
presently available Super 35mm zoom lenses quickly became apparent.
A year ago the first 2/3-inch digital camera appeared – retaining the long-established B4 lens-camera
mount and delivering a digital 4K UHD output. By NAB 2015 no less than four major camera
manufacturers were showing 4K UHD camera systems based upon the 2/3-inch image format. This paper
will review Canon’s involvement in both digital cinema lenses and in this relatively recent 2/3-inch 4K
UHD movement.
CHANGING LANDSCAPE IN DIGITAL MOTION IMAGING
The New World of Digital Cinema
Separate to the television world, large-format single-sensor digital motion imaging – generally centered
on the Super 35mm image format size – started within the Digital Cinema world and offered a digital
alternative to motion picture film origination. The original concept was to use the existing extensive
inventory of Super 35mm lenses on the newly emerging large-format single-sensor digital cameras. Most
of these early cameras had digital sampling structures of 2K (2048 x 1080) or HD (1920 x 1080). This
movement has since seen an unprecedented expansion in associated digital cameras, camcorders, and
lenses. In recent years increasingly higher digital sampling structures have become more attractive to
those producing theatrical motion pictures – with 4K currently very popular – and this has spurred a broad
and rapid development in 4K lenses and cameras for cinematography.
The New Multi-format Television Environment
Over the past decade the broadcast television world has been slowly migrating to a true multi-format
production environment. On the imaging level this encompasses program origination using different
image format sizes for camera image sensors; on the digital level it entails different digital sampling
formats. Multiple image format sizes in lens-camera systems offer a broad diversity in television camera
sizes, configurations, and shooting expediencies as well as important choices in the creative look of a
broad range of television program genres. And separately, while HDTV delivery services are largely
based upon two separate standardized digital sampling structures – 1920 x 1080@59.94i and 1280 x
720@59.94P – the origination of these are now sometimes at higher level digital sampling structures.
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Broadcast Television – a World of Multiple Image Format Sizes
On the imaging front for HDTV television production – the longstanding 2/3-inch image format size
remains the bedrock for both television studio and for outside broadcast (OB) live event production (that
cover most sporting and major events). However, in the arena of broadcast news, smaller image formats
– such as 1/2-inch, 1/3-inch and variants on the latter – have become ubiquitous. Further variants on the
latter – in the form of both tri-sensor and single sensor camcorders – have significantly broadened digital
HDTV image acquisition choices in terms of costs and mobility.
More recently, large-format single-sensor digital HD / 2K motion imaging cameras – largely of the Super
35mm image format size – are being enthusiastically adopted for a variety of television program genres
because of the different cinematic look they impart. Indeed, even the full frame image sensor DSLRs
have incorporated digital HD video capabilities and are being mobilized for certain television programs
inserts because of their particularly unique look.
Broadcast Television – a World of Multiple Digital Sampling Formats
On the television digital image format sampling front – there is also a migration underway. Many
contemporary high-end 2/3-inch studio cameras can originate in 1080/59.94P and be subsequently
converted to either of the 1080/59.94i or 720/59.94P HDTV formats for distribution to the home. By
having the masters in 1080/59.94P their archival value is increased. Similarly, many of the contemporary
Super 35mm digital camcorders record only in progressive formats – such as 23.98P / 29.97P / 59.94P –
and are also later (and easily) converted to these same two digital HDTV distribution formats.
In addition, on the temporal front, HDTV originations at increasingly higher frame rates in outside
broadcast camera systems have also grown in popularity by their support of an expanding use of Super
Slo-Mo in sports replays.
Broadcast Television – Enter 4K UHD
In 2012 the ITU international standardization organization published a global recommendation for the long
term advance of television production [1] –– having both
3840 (H) × 2160 (V) and 7680 (H) × 4320 (V)
sampling formats at a variety of progressive frame rates up to 120P. The 3840 x 2160 format is
sometime labeled 4K UHDTV. There are now many Super 35mm cameras and lenses available to
support this particular format. This 4K UHDTV format is gaining the attention of some of the world’s
broadcasters and producers of television programming. Super 35mm single sensor cameras are already
being used on many outside broadcast live events to support digital zooming in replays of fast action
situations on the field.
Broadcast Television – the New Era of 4K 2/3-inch Lens-Camera Systems
As broadcasters experimented with the new 4K UHD television production format it quickly became
apparent that existing “long” zoom lenses for the Super 35mm image format size fell far short of the focal
ranges to which they are accustomed in the world of HDTV program origination. This is true in the studio,
in portable EFP origination, and most especially in coverage of sporting and other major live outside
broadcast events. And indeed, the industry has been quick to respond to this void.
Over the past year and a half no fewer than five of the world’s major broadcast camera manufacturers
have introduced 2/3-inch tri-imager (four imagers in the case of one company) cameras – that maintain
the globally established B4 lens-camera mount – that can deliver 4K UHDTV digital outputs. From the
outset, some of these cameras systems are upgradable – both spatially (HD to UHD) and temporally
(various multiples of the standard 60i frame rate) for slow motion capture. This is in recognition of the
industry uncertainty as to the pace of penetration of 4K UHDTV to the homes of consumers.
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