Abstract
Data
for this section relevant to the modified version of
the Sony HDW900 camera, with hardware and software revisions
issued in 2003, and referred to as HDW900/3. It is little
changed from the earlier version, but the changes have
significance in that some settings for the original camera
nmo longer do what they should.
This
model developed from the earlier HDW700, which was
a 1035-line camcorder, operating at 59.94 or 60Hz,
interlaced. The later models are 1080-line and will
also operate at various frame rates from 23.976 to
30Hz progressive, and 50 to 60Hz interlaced. They
record a maximum data rate of about 144Mb/s onto
Betacam-like tape, the transport speed varies with
frame rate so tape duration depends on frame rate.
The
camera is based on the familiar form of the Beta
camcorder and is used mostly for portable, single-camera
work. It has many internal menus for setting the
performance, such that it can then be used without
external controls. It is not ideally suited to multi-camera
operation, although it can be controlled remotely.
The
menu settings result from several measurement and
usage sessions, mostly attempting to get a good "film-look",
and the settings reflect that. It is useful to think
of the camera, when used in this way, to be mimicing
a film camera and neg-scan telecine, with "best
light" transfer to tape. It is always assumed
that a grading operation should be used in post-production,
the settings give the colourist the same range of
options as with film. The laboratory tests were made
using a BTS LDK9000 as a reference camera, of the
type used in the Eureka 1250-line system. The values
for Gamma, Black Gamma and Knee allow nearly 3 stops
of over-exposure and one of under-exposure relative
to normal operation, although the knee has two points
of inflexion which could conceivably cause colour
contouring (although this has not been observed in
practice). This setup approaches a film-look, provided
that Detail correction is either off or set to a
low level. Images are generally sharper than even
for 35mm film, this can be an issue for production,
but can generally be dealt with by using filters
or some post-production softening. For use in Sport
or Light Entertainment, it would probably be beneficial
to switch off the Black Gamma, and to increase Detail
Level to zero (factory setting).
Many
of the menu items have little or no effect on image
quality. Those that do so are highlighted. The full
set of menu items is given for completeness.
One
major new feature of the camera is custom-generated
gamma curves, whereby the user can define a transfer
characteristic and download it to the camera on a
memory stick. An editor is available from Sony, to
prepare the data, users should refer to Sony for
more information on this.
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Keywords
camera,
colorimetry, gamma, knee, aperture correction, detail enhancement,
film look, shuttering
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