The world’s major professional video manufacturers have introduced
a diverse range of low-cost tapeless HD camcorders and tape-based
HDV professional camcorders. Various design strategies have been
adopted by the manufacturers to decisively drive down the costs
of these HD acquisition systems. They include different image format
sizes, subsampled imagers, and contemporary digital recording techniques.
In support of these products Canon designed an entire family of
cost-effective HD ENG/EFP lenses that seek to match both the performance
and the costs of these diverse and still-emerging HD acquisition
systems. To distinguish this level of lens within the overall Canon
HD optical hierarchy they are identified by the logo HDgc –
to clearly differentiate them from the already established high
performance HDxs line of 2/3-inch portable lenses.
These acquisition systems have been developed in response to the
broadcast industry’s rapidly growing interest in transitioning
to HDTV Newsgathering, HD reality shows, and other lower-budget
HD productions. They also directly address the increasing adoption
of HD digital origination by the growing independent filmmaking
market sector. In addition, they are anticipated to foster growing
interest in HD within the broad B2B market sectors. To support this
extensive flexibility in HD acquisition systems, the new HDgc family
includes 2/3-inch, 1/2-inch, and 1/3-inch lenses.
The KJ10ex4.5B IRSE is a portable HDTV production lens within the
2/3-inch image format sector of the HDgc family. This particular
lens is intended for users whose foremost priority is a lens that
delivers a generous range of focal lengths combined with an exceptional
wide field of view in a lightweight mobile package. It was specifically
designed for the new cost-effective 2/3-inch acquisition systems.
It is an important member of the emerging HDgc family in terms of
facilitating HD imaging with equivalent operational capabilities
as the established 2/3-inch SDTV systems.
ABOUT THIS LENS
Canon’s breakthrough technologies and powerful computer-aided
design techniques produced the KJ10ex4.5B IRSE, a standard HDTV
lens with an excellent performance-cost optimization. In addition,
it offers focal lengths of up to 45mm (or 90mm with extender) and
a wide field of view of 93.7 degrees. It is a design that directly
responds to the expressed creative desires of broadcasters and HD
producers for low-cost HD acquisition system.
The KJ10ex4.5B IRSE represents a fine compromise between the demands
for mobility in a handheld HDTV camera system and the high imaging
performance requirements for HDTV production. The requisite optimization
strategies to achieve this balance sought a high MTF over the entire
image plane, minimization of chromatic aberrations, and maximization
of image contrast. Preservation of a high MTF at the wider-angle
focal lengths (where scene detail can be particularly high) was
a special priority.
Relative light distribution was optimized for the more open aperture
settings and this uniformity of brightness across the image plane
combined with the high contrast and excellent picture sharpness
produces vividly clear HD pictures. Contrast was extended by careful
control of black reproduction – with optical and mechanical
design innovations that substantially reduced flare, veiling glare,
and any internal reflections. Tight control of the geometric distortion
at wide-angle settings constituted another central design imperative.
The lens spectral transmittance characteristic was closely coordinated
with that of all of the major portable cameras to ensure adherence
to the HDTV colorimetric standards and to additionally support flexible
creative control of color reproduction.