High Definition - the camera family cont'd...
Thomson Viper
The Viper is the cine style variant of the Thomson Grass Valley LDK6000. It is designed with a film style of operation in mind but not sacrificing the operational advantages of video. It is not a camcorder.
It is a compact head with a ccz style connector on the rear.
It is the only camera at the moment to have a output direct from the ccds. The current terminology to describe this camera is that it is a camera with a 444 output.
Well what is 4:4:4? In TV land we have to operate gain, detail and matrix setting in camera to select a narrow band of information that fully occupies the somewhat limited bandwidth of sampled TV recordings.
When I first started using digital slomo cameras in the mid nineties I was told that I could select gain, detail and matrix after the recording! A revelation.
4:4:4 enables virtually all of the output of the ccds to be recorded,(if you have a hard disk recorder that can cope with the huge data stream) so gain, detail matrix and gamma settings can be adjusted in post production. This means that highlight control and colour grading is performed in post rather than in camera. Typically this results in a one stop increase in dynamic range and more scope to manipulate colours.
Although the camera outputs raw data from its ccds it is still restricted to a modest 1920x1080 pixel output with the ccds sampled at 12 bit and converted to 10 bit log.
On location the DP need only control exposure, focus, frame rate, shutter and framing.
Some DPs do not like the concept of their images being altered in post, for others post grading it is just another tool and an opportunity for a few more days work.
We could have had 4:4:4 cameras years ago but there was little to be gained as TV sets aren't high fidelity displays and there was no convenient way to record 4:4:4. With the advent of video to film transfers the prospect of actually needing all the information from the ccd started some head scratching. The advent of The Directors Friend in 2000 which was the first portable Hard disk HDSDI recorder designed for location use, began the ball rolling. It is the size of an electric piano and is connected by cable to the camera. Its immediate use was recording uncompressed HDSDI from any HD camera.
A year later The Directors Friend was adapted to record 4:4:4.
Like most HD cameras and camcorders the Viper also has a HDSDI output which can also be recorded either on a uncompressed disk system or a compressed tape format.
The Viper is also unique in that it can scan and output 1920x1080 in 2.35:1 aspect ratio. It can achieve this by using ccds consisting of 1920H x 4320V pixels. Wow a super HD camera! No... unfortunately for the moment at least, the camera can only output 1920x 1080 pixels or pixel groups at a time. It groups the vertical sub pixels together so that the vertical line count can be set to 720, 1080 within a 16 x 9 format or 1080 within a cinemascope format of 2.35:1
It is the only camera to have this feature of full height (1080) cinemascope. This output can be 4:4:4 or HDSDI. The sheer quality of the data is a draw back for long form work although Sony's new HDCAM SR format field recorder SRW1 will be a natural partner for the Viper and indeed Sony's and others 444 cameras.
In the meantime the Viper offers studio based HD cinemascope format with extraordinary depth of field under low light being recorded on the HD tape format of choice or on the digital piano if you can find a post house willing to have a go with dealing with the data.
In HDSDI mode it has full control of gammas, detail, matrixes etc. It has a useful zoom function on the viewfinder to check focus.
Sony HDC F950
This is a upgraded HDC950 camera with 4:4:4 output. There is a T option for this camera, that splits the ccd block from the camera making a small camera head. It does not have a 10-bit log output like the Viper.
Other Cameras...
Hitachi SK3300p Studio camera 1080i 720p.
Hitachi SK9100P Studio camera 1080i only.
Hitachi DK-H3A small 3 chip B4 mount box camera for graphics and rostrum 1080i.
Ikegami HDL-20 a tiny 2 chip remote head HD camera, initially 59.94 with a 24p version coming soon with great promise since it will use small c mount lenses.
Ikegami HDL10 single chip remote head 1035i HD camera.
Ikegami HDL40 3 chip CMOS box camera
Ikegami HDK-79EX camera 720p or 1080i only studio camera.
Panasonic AK-HC900 box camera with B4 mount producing native 720p.
Panasonic-HDC 20A camcorder 10 bit, 59.94 only.
Sony HDW700 HDCAM camcorder (discontinued) 10 bit 59.95 only 1035i
Sony HDW700A HDCAM camcorder (discontinued) 10 bit 59.95 only 1080i
Sony HDW750 discontinued 60i only camera, not to be confused with the 750p which is 25p /50i camera.
Sony HDW 730 replacement for 750 it records 50i as well as 60i. Now renamed the HDW730S
Sony HDC950 Sony's studio camera. A remote head kit, HKC-T950, can be bought to make this the smallest 1920 x 1080 camera.
Sony HDCf950 New version of HDC 950 to be released 2004 with 444 output will also work in 444. "T' version for remote head mode.
Sony DXC H10 1920 x 1035i One of the first HD box cameras.
Sony X300 3 chip HD box camera using 1/2 inch chips 1440 x1080 pixels.
Thomson LDK6000 Mark II multi format, 24p capable studio camera. A Viper without 444. A very popular OB and studio HD camera.
JVC DZ-VCA3U a 3 chip remote head mains only medical camera with c mount.
1125 lines 750 x 750 pixels. Marginal HD quality.
Dalsa Origin the first of the non TV standard digital high resolution cameras. It uses a Bayer chip to create colours on its single chip.
Arri D20 Single chip CMOS sensor 2k camera using Bayer filter.
Kinetta, offers the promise of intercgangeable sensor and dockable hard drive to record 444.
Genesis, Sony Panavision 12 million pixel single chip CCD camera in super 35mm format.
Mind your Ps
It is possible to deinterlace a 60i picture turning the 2 field per frame into a one field frame image. By definition this becomes a progressive frame, albeit a progressive frame with half the resolution removed! By then doubling the remaining lines a new picture is made which is in resolution terms is softer than the original but produces smooth motion when replayed at 24 or 25fps.
Rate card
The ATSC television system includes four basic digital image formats; two high definition and two standard definition. The 1920x1080 and 1280x720 images are high definition while 704x480 and 640x480 are standard definition. These are the transmission standards that get the picture from broadcaster to home set. In respect of live broadcasts the truck needs to output the standard that is being transmitted. It is possible to convert a 1920x1080 camera signal in the truck to another format.
Some cameras have dual output HD and standard def. Within these formats there are varying frame rates.
Every manufacturer on the planet calls 720p a HD format. Everyone but Sony who don't have a way of recording it even though they do have a studio camera that is 720p switchable. Upconversion or uprezing from the many digital and HD formats in the edit to 1920x1080 is not uncommon. Conversion cards are available for ccus to convert 60i cameras to "P" formats. This is not the same as scanning the ccd in "p" mode, far from it!
So we must be very careful of the pedigree of the picture:
- What quality the lens?
- How many CCD chips?
- Number of effective pixels on the chip?
- What is the "native" scanning rate of the CCD?
- Are they sampled?
- What bit depth?
- Recorded at what compression rate?
- On which recording format?
- What losses in the edit to get from camera format to editing format?
The numbers are one thing, looking at the picture is another and in most cases the more revealing. It goes without saying that you must know the specification of the display device that you are using to measure your standard. Use your eyes!
Accept that our eyes play tricks, we have poor colour memory - we are more sensitive to tones in the skin than blue tones in the sky. We see some artifacts and miss others.
These factors are not at all represented in the numbers comparisons between cameras.
Since major manufacturers are keen not to make a distinction between 1440 x 1080 and 1220 x720 and 1920x 1080, they only have themselves to blame when a $4k "HD" consumer camera gets plenty of attention! I refer to the JVC HDV camera.
When it comes to evaluating HD, use your head and your eyes.
© Michael Brennan 2006
