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Posted by PTravel on 10/07/53 11:51
"Skookum" <ndale@uniserve.com> wrote in message
news:1151469366.437263.113780@j72g2000cwa.googlegroups.com...
> Thanks for the information and I also am interested in the last comment
> you make. I do not know much about competing formats: are you saying
> that the Mini DVs or some other format os preferable? Although I won't
> be into editing much (I suspect), image quality is important and I'm
> wide open to your advice on this.
DVD is a delivery medium, not a capture medium. Video DVDs store video
using mpeg2 compression. Mpeg is a lossy, temporally compressed format.
"Temporally compressed" means that the transcoder uses frames both ahead and
behind a reference frame, calculates what has changed, and then stores only
the changes. For mpeg2 to yield high-quality video, it must do multiple
analysis passes to calculate optimum compression. Commercially-produced
DVDs use multiple analysis passes on high-quality transcoders, which is one
of the reasons they look so good. The built-in hardware transcoders on
camcorders do single-pass analysis and do not result in optimum compression,
so video quality suffers. DVD-compliant video also tops out at a bit rate
of approximately 8-10 mbps and uses compression ratios of about 10 to 1 (or
more). Note that when a camcorder manufacturer claims "DVD quality" video,
they do not mean you will get the same quality of video that you're used to
seeing on commercial DVDs. What you get is "DVD quality," all right,
because it comes from a DVD. It is, however, degraded video and does not
remotely approach commercial DVD quality (or even what you can get burning
your own on your home computer using good quality consumer software).
miniDV uses the DV-25 standard. It is not temporarlly compressed, i.e. each
frame is compressed individually, without reference to preceeding or
forthcoming frames. This allows for very efficient, optimized compression
in the camera. DV-25 compresses at about a 5 to 1 ratio. DV-25 has a data
rate of 25 mbps, i.e. 2.5 to 3 times more video data per second than DVD.
Accordingly, miniDV is considerably less compressed and captures
considerably more data than DVD.
If you looked at _only_ the format in which the video is captured, miniDV
yields an obvious and rather dramatic advantage, i.e. all things being
equal, video from a miniDV camcorder will look significantly better than
video from a DVD camcorder.
However, there are other factors that determine video quality besides
bit-rate, compression ratio and temporal vs. non-temporal compression.
Video quality is also determined by such factors as sensor size, quality of
electronics and, most significantly, quality of the lens on the camera.
DVD camcorders are designed to appeal to the same consumers who purchase
disposable film cameras, i.e. those who are "technically challenged," and/or
want a very simple and inexpensive solution to capturing images. As a rule,
DVD camcorders have tiny CCDs, low-quality lenses and sell themselves on the
basis of gimmicks, e.g. built-in "special effects," "digital" zooms that
produce an unusable and degraded image, long optical zooms that further
reduce light sensitivity and introduce all sorts of optical defects,
distortions and chromatic aberrations, etc. Note that there are plenty of
miniDV cameras with these characteristics as well -- crappy cameras aren't
confined only to DVD camcorders, and manufacturers produce low-end miniDV
camcorders that will produce video every bit as bad as that from a DVD
camcorder. However, miniDV has evolved into a stable prosumer/professional
format -- feature films have been shot on miniDV ("Open Water" and "28 Days
Later" are two that come to mind), the BBC uses miniDV cameras for
electronic newsgathering (ENG), and good miniDV cameras can produce video of
the the highest quality. Note, too, that, while there are prosumer miniDV
camcorders, e.g. the Sony VX2100 and Canon XL2, there is no such thing as a
prosumer DVD camcorder.
If you care about video quality, get the best miniDV camcorder you can
afford. Sony and Canon make some pretty decent mid- to high-end consumer
machines, but you won't find them on sale for $300. If you really care
about video quality, get a 3-ccd machine (3 sensors, one for each primary
color, instead of a single sensor with a mosaic filter on top). However, do
_not_ get a low-end Panasonic 3-ccd machine -- these were designed
specifically to sell to consumers who had heard about the advantages of
3-ccd, but didn't want to spend the money for a prosumer machine (the VX2100
has a street price of around $2000, the XL2 around $3,000), and represent
good marketing rather than good engineering. You'll get better video from a
comparably priced single-ccd Sony or Canon.
Things to look for:
The bigger the CCD the better -- 1/6" is too small, and will have absolutely
dismal low light performance. You won't be able to use it indoors or at
night. 1/4" is better, but still not very good. A camera with a 1/3"
sensor would be best (again, for comparison, the VX2100 uses 3 1/3"
sensors).
The bigger the physical size of the lens, the better. More glass passes
more light, which will improve the low-light performance. Also, to get a
reasonably wide field of view requires a large lens.
Look for Zeiss optics -- not required, but an indicator of a good-quality
lens.
OIS (Optical Image Stabilization) provides smoother looking video than EIS
(Electronic Image Stabilization). On Sony machines, OIS is called "Super
Steadyshot," whereas EIS, in Sonyspeak, is just "Steadyshot." I don't know
whether there is such a thing as a camcorder without stabilization of some
sort, but it's an absolute requirement if you don't want your video to look
like Dad's 8mm movies.
DON'T get more than a 10x or 12x zoom. As I indicated, long zoom ranges on
consumer camcorders degrade the image and lower the light transmissivity of
the lens. Also, no one can hand-hold more than 12x without the image
shaking so badly (even with image stablization) as to render the resulting
video unusable, so this is useless feature.
DON'T be fooled by gimmicks like built-in special effects, wifi, BlueTooth,
USB connectors, so-called "digital zoom" (which merely lowers the resolution
of the resulting image), still imaging capability (see below), etc. The
standard for transferring video from digital camcorders is the 1394/Firewire
port. USB is only for transferring still images, or streaming low-quality
video, e.g. as a webcam.
DON'T buy a camcorder based on its still imaging capability. As a rule, the
higher resolution for the still image capability of a camcorder results in
lower low-light sensitivity and, usually, more digital artifacts in the
video. No camcorder will produce stills remotely approaching the quality of
even an inexpensive p&s digital still camera.
And, finally, a word about editing. Not everyone wants to edit their
videos, and that's fine. However, if you think you might ever want to, know
that, unless you're going to do only simple cuts-only edits, editing the
mpeg2 video from DVDs is difficult to impossible. You'll be limited to a
very narrow range of entry level consumer products, and you won't be able to
do the kind of sophisticated titles, transitions, effects and corrections
that even the most basic DV-codec-encoded AVI editors (which is what you get
when you transfer miniDV to a computer) can achieve. You might not wish to
edit your video some day, but you also might find that your DVD-Rs are
unreadable -- no one knows the archival quality of these things, though I
have DVD-Rs that I burned five years ago, some of which are now error-ridden
and unreadable. miniDV tape, on the other hand, is stable and, like all
digital tape, when properly stored will last for decades.
Probably more than you wanted to know, but there you go.
>
>
> PTravel wrote:
>> "Skookum" <ndale@uniserve.com> wrote in message
>> news:1151443423.370449.262600@u72g2000cwu.googlegroups.com...
>> >I am on a brief visit to Germany and England (I normally live in North
>> > America). I was considering buying a DVD Camcorder but heard that there
>> > may be a compatibility problem since most of Europe uses PAL format
>> > while the Americas rely on NTSC. I am completely ignorant of what this
>> > means though I did have a look at the relevant Wikipedia articles.
>> >
>> > My bottom line question is whether I should forget about buying over in
>> > Germany or Britain (I have found some great deals on Sonys and
>> > Panasonics)?
>>
>> You'll need an NTSC camcorder for use in North America, and, to the
>> extent
>> they're available, will be more expensive in Europe. NTSC and PAL are
>> incompatible video standards, the latter being common in most of Europe
>> (SECAM being a less common, but equally incompatible, European standard).
>>
>> Since you're buying a DVD camcorder, I assume neither video quality or
>> anything more than minimal editing is of concern to you.
>>
>> >
>
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