Specs of Sony Digital8 TRV820

[Steve McDonald]

Below is the response I got from Sony about my questions concerning
their new TRV820. Below that is my message to them.

Steve McDonald

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Dear Sony Customer:

Thank you for contacting Sony.

The DCRTRV820 has 460,000 pixels. Features and specifications are
always subject to change.

We have no information as to whether or not a Digital8 VCR will be
marketed.

You will not be able to control the Digital8 from the Hi8 camcorder
operation.

The answers to many customer questions may be found on the Product
Support Solution Page at the following URL:

http://www.sel.sony.com/SEL/consumer/ss5/custserv.shtml

Thank you for the opportunity to be of assistance.

Sincerely,
Sony Internet Department

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Questions About Sony Camcorder:

Model Name: DCR-TRV820

MESSAGE:
          
For some time the Digital8 model DCR-TRV820 was listed on your
website and in some publications as having 680,000 pixels on its CCD.
However, your website now shows this model as having only 460,000 pixels
on its CCD. What is the true number of CCD pixels on this model?   If
it only has 460K pixels, why was it shown to have the greater number
previously?  

Also, when will you produce a Digital8 VCR?

Can a Digital8 camcorder be hooked-up to a Sony Hi-8 camcorder and
be controlled for on/off record-pause by the Hi-8 for live Digital8
recording from the analog output source of the Hi-8 camera? In other
words, could the Digital8 camcorder be carried as a "stand-alone"
recorder, in a bag and be wired to the Hi-8 camera's output and have the
record-pause button on the Hi-8 be able to turn the Digital8 recorder on
and off?

Thank You,
Steve McDonald

[Joe]

In place of having actual demo units, some stores around here have little
note-pads / tear-off sheets of the various D-8 camcorders. I have these for
the 120, 320, and 720 models.

According to these, the CCD has 460k gross pixels (290k effective). The
imaging chip is 1/4", with the term "720H" beside it, which must mean 720
pixels horizontally. If so, then 460000 / 720 = 638.8888, indicating that
the CCD chip has a resolution of 720 x 640 pixels (?). This is a ratio I
don't understand - it isn't 4/3. Unless it is larger just to perform the
electronic image stabilization, in which case the 485 active lines in NTSC
is taken from the central 640 lines of the CCD. In this case, assuming
square pixels and a 4/3 aspect ratio, then the actual video image would have
a resolution of 646 (H) x 485 (V), giving 313,310 pixels. A little more
than the stated 290k effective pixels.

Since the Sony literature says 290k effective pixels, the effective
horizontal pixels must be either 598 or 604 (depending on whether there are
485 or 480 active scan lines). But the ratio of 480:600 is not 3:4, so
again I don't know how to make sense of these numbers, unless the CCD chip
has non-square pixels.

By the way, the lens specs show an effective f range (converted to 35mm
equivalent) of 48 to 1200, which is exactly 25x, which is really wicked by
any means. Throw on a decent wide-angle lens (say, .4), and you have a
telephoto lens equivalent to f20 -> f480.

A Sony digital-8 brochure shows a comparison of the recording track layout
of DV and Digital-8. In this diagram, they show DV as having a track width
of 6.5 mm and 1 frame being recorded onto 10 consecutive tracks. In the
Digital-8 diagram, they show the track width as being 8 mm and 1 frame being
recorded onto 5 consecutive tracks. Since this is digital information,
there is an absolute, fixed number of data points being stored for each scan
line, and this is the effective horizontal resolution of the system. And if
Digital-8 is equivalent to DV, then they have to write information to the
digital-8 tape at a faster rate then the DV tape to have the same
resolution.

As an aside, I wonder if all these companies are confusing "lines of
resolution" with horizontal pixels. In photography, you need a black and
white space to make a single line, but in digital imaging a similar line
would require 2 pixels (a black one followed by a white one). So, a claim
of "500 lines of resolution" would need 1000 horizontal pixels to reproduce.

In any case, it's clear that for video recording a camcorder wouldn't need
more than 300k pixels, unless electronic image stabilization is used. If
camcorders go beyond the 460k amount, then the extra resolution would be a
selling point for still image capture. As such, I believe there is a
particular still image capture mode for these Sony camcorders where you can
extract a 720 x ??? image (but don't quote me on that).

As for your other question, all these camcorders (well, the north-american
ones anyways) can record from a line-input (S-video) and from 2 other jacks
- Sony calls one a "Special video in/out" and the other is "iLINK DV
In/Out". The video from the Hi-8 could be fed into the D-8 camera no
problem, but I don't see how you could slave the VTR transport controls from
the Hi-8 to the Digital-8, unless that is possible using the LANC jack ?