news:29188-433B0A7C-77@storefull-3158.bay.webtv.net...
>
> I'm considering getting a JVC GRD250 MiniDv Digital Camcorder. (it's
> only $200 brand new)
>
> I have a Zenith DVD Recorder (DVR 413) that has a firewire input which
> should work well for capturing the MiniDV's video.
>
> After a quick search to see what I could find out about the JVC, I
> discovered that it has a '680K pixel CCD w/340K effective pixels for
> video'.
>
> My question is; does the '340K effective pixel' represent the normal
> video quality (and/or resolution) for a low-end MiniDV?
>
> Is MiniDV video like Hi-8 camcorders in that the video to tape
> resolution is less than what the camcorder will actually take?

>
> If anyone is familiar with this model, please let me know what you think
> of it.
>
> Thanks for any help.
>

>
>
>
>
> PTravel wrote:
>
> " Resolution is a different issue that is not necessarily related to the
> number of pixels on the sensor. Hi8 was capable of around 400-450 lines
> per inch. MiniDV, in theory, is capable of up to 525 lines per inch. In
> practice, however, you will not reach those kinds of resolutions which
> cheap consumer equipment. Maximum resolution is a function of optics and
> electronics, as well as sensors. A 340k sensor machine, theoretically,
> could reach 525 lines, but a cheapie consumer model almost certainly
> won't -- I've heard of some consumer camcorders that resolve as little
> as 275 lines, which puts them in VHS territory. "
>
>
> ^^===============================^^
>
> Well it looks like 340K effective for video is normal for a low-end
> miniDV camcorder.

>

"PTravel" <ptravel88-use***@yahoo.com> wrote in
news:3q37n0Fd30seU1@individual.net:

>
> <al***@webtv.net> wrote in message
> news:24682-433C590F-31@storefull-3153.bay.webtv.net...
>> PTravel wrote:
>>
>> " miniDV resolution is 720 x 480 pixels (NTSC) for a total of
>> 345,600 pixels, i.e. approx. 340k.
>>
>> ^^================================^^
>>
>> The info I found on the JVC camcorder said that the video
>> resolution is 640 x 480. That
>> may be the resolution of what the tape can record and not the
>> camcorder itself.
>
> It's not.  I'm not familiar with the JVC camcorder.  However,
> miniDV is a standard that uses 720 x 480 pixels for NTSC video
> (which is the standard used in the US).  If the camcorder can't
> generate a digital video stream that is 720 x 480, it doesn't
> conform to the standard.  This means that (1) it will have reduced
> resolution, and (2) you may have trouble editing it. 640 x 480 is
> the VGA standard, and a lot of media software and hardware can
> handle it.
>
> Video resolution encompasses two separate aspects -- the number of
> pixels per frame, e.g. 720 x 480 or 640 x 480, and the extent to
> which fine detail can be resolved, measured in horizontal and
> vertical lines per inch.  The two are related, but the fact that a
> camcorder has 720 x 480 pixels does not necessarily mean that it
> can resolve fine detail well.  The number of horizontal by
> vertical pixels only describes the digital format of a frame. The
> lines-per-inch resolution measures the actual resolving power of
> the system, and is a product of the quality of the lens, the
> accuracy of focus, the dynamic range of the sensor, and the
> ability of the electronics to exclude noise.
>
> As I mentioned in my earlier post, the miniDV allows for a
> theoretical maximum horizontal resolution of 525 lines per inch.
> However, most low-end consumer miniDV camcorders will not approach
> this.  A 640 x 480 camcorder sounds like a real cheapie -- I
> wouldn't expect much from it.
>
>
>>
>> I have a Hi-8 camcorder now, but if I use it for shooting video
>> of anything that's farther than
>> 50' away (w/o zoom) the subject is very grainy and hard to see.
>> (what's recorded on tape)
>
> What you've described relates to the horizontal and vertical
> resolution, i.e. how many lines per inch your camcorder can
> resolve.  There are many, many factors that effect resolution.
>
>
>> I'm hoping that miniDV's better resolution will be able to handle
>> objects that are farther away.
>
> As I said, the theoretical maximum resolution of miniDV exceeds
> that of the theoretical maximum of Hi8 -- 525 lines per inch
> versus 450 lines per inch, respectively.  However, these are only
> theoretical maximums.
>
> I have an old Sony TR-600 Hi8 camcorder. This was a
> close-to-the-top-of-the-line consumer camera Sony manufactured 10
> or 11 years ago.  It has better resolution than many low-end
> consumer miniDV camcorders that are on the market today.  However,
> I also have a Sony VX2000 miniDV camcorder.  This is a prosumer
> model that produces high quality video.  Sony claims that maximum
> resolution, i.e. 525 lines, for this camera, and I have no reason
> to disbelieve that.
>
> To answer your question, a cheap consumer miniDV camcorder will
> not necessarily have better resolution than your Hi8 camcorder,
> and may have dramatically poorer resolution.  It will also,
> undoubtedly, have far poorer low light performance (though that's
> another discussion entirely).  As I said, there are miniDV
> camcorders on the market that barely achieve VHS resolution (250
> lines per inch or so).  Merely switching formats does not ensure
> that you'll get better resolution.
>
>
>
>>
>>
>> PTravel wrote:
>>
>> " Camcorders that have higher density sensors usually use them
>> for still imaging. Some (but, generally, not bottom-of-the-line
>> machines) can do pixel subsampling, i.e. using the additional
>> pixels to "average," producing a slightly better image. "
>>
>> ^^================================^^
>>
>> Yes, the info on the JVC said Image resolution (still, as opposed
>> to video) is 1024 x 768.
>
> Still resolution is meaningless to video resolution, except that
> higher density sensors tend to have poorer low-light capability
> and introduce more artifacts to the video.
>
>
>>
>> It also mentions that the JVC uses a 'super high-band processor
>> that restores the high-band components of the luminance signal to
>> ensure a crisp picture with 520 lines of resolution' for video.
>
> 520 lines would be great.  I don't believe it, though, if the
> video resolution is 640 x 480.
>
>>
>>
>>
>>
>> PTravel wrote:
>>
>> " Resolution is a different issue that is not necessarily related
>> to the number of pixels on the sensor. Hi8 was capable of around
>> 400-450 lines per inch. MiniDV, in theory, is capable of up to
>> 525 lines per inch. In practice, however, you will not reach
>> those kinds of resolutions which cheap consumer equipment.
>> Maximum resolution is a function of optics and electronics, as
>> well as sensors. A 340k sensor machine, theoretically, could
>> reach 525 lines, but a cheapie consumer model almost certainly
>> won't -- I've heard of some consumer camcorders that resolve as
>> little as 275 lines, which puts them in VHS territory. "
>>
>>
>> ^^===============================^^
>>
>> Well it looks like 340K effective for video is normal for a
>> low-end miniDV camcorder.
>
> 340K isn't "normal" -- it's what's required to produce a 720 x 480
> image. My VX2000 has ccds with 380k pixel sensors, though it has 3
> separate CCDs, one for each primary color.
>
>
>>
>>
>> 2 more question come to mind:
>>
>> 1) What video resolution is considered 'broadcast quality'?
>
> I'm not sure if there's an actual standard, though there may be.
> Broadcast-quality monitors usually resolve 600-700 lines.
>
>>
>>
>> 2) Does miniDV and Hi-8 tape record video at less resolution than
>> the camcorder is capable of? (I've recorded the Hi-8 camcorder's
>> signal directly into a DVD recorder and it seems to yield a
>> better picture than what plays back on the Hi-8 tape)
>
> I'm not quite sure what you're asking.  As I said, resolution is
> the result of the particular combination of lens and electronics,
> as well as the particular standard employed.  The Hi8 format can
> accomodate up to 450 lines per inch, but very few camcorders are
> going to reach that. However, some do. The miniDV format can
> accomodate up to 525 lines per inch, but very few camcorders are
> going to reach that.  However, some do.
>
> As for getting better results taking the analog video signal from
> a Hi8 and recording it to a DVD recorder, there are so many
> variables that it's impossible to say what's happening.  Analog
> signals must be digitized to make a DVD.   The digitization
> process is done by the DVD recorder in realtime.  The resulting
> digitized video is then compressed to DVD-compliant mpeg2 and
> written to the DVD.  Mpeg2 compression is a black art that is
> dependent on the particular software employed.  Frequently,
> consumer-grade DVD-compliant mpeg2 video transcodes look soft --
> this is done to repress digital artifact that result from the
> conversion of analog to digital.  Many people prefer a softer
> picture to a picture filled with jaggies and other digital
> artifacts.  This may result in a subjective judgement that the
> picture is "better," but it really isn't.
>
> MiniDV camcorders perform the digital conversion internally.  They
> output a digital video stream (and some of them can also output
> analog video as well).  Again, the quality of the video is going
> to be dependent on all the components that make up the camera --
> lens, sensors, electronics, etc.

>
> Consider that you might be showing the tape on a 12" TV and I might
> be using a 24" TV - or vice versa... Surely you don't believe that
> the picture on the smaller TV shows around 5000 lines in its roughly
> 10" height, while the other shows around 10000 lines.
>
> Regardless of the resolution of the picture, miniDV tape has a fixed
> format with 720x480 pixels (NTSC), so a source containg a different
> number of pixels is interpolated or extrapolated to fit.
>
> HTH,
> Gino
>
> --
> Gene E. Bloch (Gino)
> letters617blochg3251
> replace the numbers by "at" and "dotcom"