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Abstract
Data for this addendum is taken from a short examination of one production model of the Sony PMW-EX1 HDTV camcorder and its manual and from a brief comparison with the EX3. These are HDTV camcorders (the EX1 with integral lens, EX3 having interchangeable lenses) of similar size to the Z1 but recording only onto solid-state storage. They have 3 ½” cmos sensors of 1920x1080 pixels, and therefore should qualify fully as HDTV cameras. Recording HDTV uses MPEG2, 8-bit, 4:2:0 colour sub-sampled, at 35Mb/s (with variable bit rate, maximum 35Mb/s, 1920x1080 interlaced/progressiveor 1280x720 progressive or at 25Mb/s (with constant bit rate, 1440x1080) onto solid-state SxS cards. There is no SDTV mode available.
The cameras are relatively light (about 2.8kg in including battery) and have an integral viewfinder (3½” lcd), and seems aimed at the high-end professional and full broadcast markets, even though the broadcast market would normally demand an image format larger than ½” and removable lens, and a recording format with higher bit-rate. The EX3 has genlock and time-code inputs, and a remote control socket, so may well be usable in multi-camera shoots.
Variable speed recording is possible, from 1 frame/second up to the nominal frame rate setting (24/25/30 when recording 1080-line, 24/25/30/50/60 when recording 720-line). The implications, for production at 25p, of setting the camera to 720p/60 and then recording a variable frame rate, have yet to be established. Perhaps the only problem would be timecode and genlocking.
There are internal menus for setting the performance, not as complex as in a full broadcast camera, but enough to control some of the important features, albeit only in “on/off” states. They are not suited to multi-camera operation since they cannot be remotely controlled. There are analogue-only video outputs (components and SD-composite via a multi-pin connector which are specific to these cameras) and digits via IEEE1394 iLink/Firewire in HDV format, USB-2 for data file transfer, and 10-bit HDSDI.
The same assessment procedure was used as for other HD cameras, partly attempting to get a good “film-look”, and the settings reflect that. However, it was not possible to fully explore some of the colorimetric features because there was no sawtooth test signal available in the normal menus (a sawtooth is apparently available in the service menu). Since many camera parameters are undefined in the specifications, more measurements than usual were necessary, and the results cannot be guaranteed as explicitly as with more complex cameras. In the search for a “film-look” setting it is normal to think of the camera to be mimicking a film camera and telecine, with “best light” transfer to tape, with about 11 stops of tonal range. Assuming that a grading operation will be used in post-production, the settings attempt to give the colourist the same range of options as with film, but without achieving the full 10-stop dynamic range. The recommended settings allow about 1.5 stops of over-exposure and one of under-exposure relative to normal operation. This is perhaps not quite as good as can be achieved in ⅔” cameras, and arises from the difference in pixel size (the pixels here are smaller, so sensitivity is maintained at the expense of highlight handling and video noise).
Although there is no standard definition recording mode, the 720p mode is very clean and should be the best way to shoot should the camera be expected to produce an SD output. The quality of this 720p mode is highly unusual in any camcorder. |
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Keywords
camera, colorimetry, gamma, knee, aperture correction, detail enhancement, film look, shuttering
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