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Posted by Frank on 06/12/06 15:13
On Mon, 12 Jun 2006 09:58:34 -0400, in 'rec.video.production',
in article <Re: Varicam or Not Varicam?>,
Ty Ford <tyreeford@comcast.net> wrote:
>On Sun, 11 Jun 2006 17:45:07 -0400, Frank wrote
>(in article <ud3p82l5p5tv1715l1p48v7jm6p5pqrl6c@4ax.com>):
>
>> On Sun, 11 Jun 2006 09:47:16 -0400, in 'rec.video.production',
>> in article <Varicam or Not Varicam?>,
>> Ty Ford <tyreeford@comcast.net> wrote:
>>
>>> Hi,
>>>
>>> I was on a shoot last week that was supposed to be an HD shoot on a
>>> Varicam.
>>> The camera itself was not as tall as I remembered other Varicams. It had
>>> "DVCPro HD" printed on one side and 720P on the other. The Varicam logo
>>> looked askew as if it had fallen off and had been reglued.
>>>
>>> So looking it up on the net shows me a 1280x720 camera. The 720 I'm
>>> familiar
>>> with is 720x480. What is it about this variacam that would make them put
>>> 720
>>> on the camera rather than 1280?
>>>
>>> Regards,
>>>
>>> Ty (confused in Baltimore) Ford
>>>
>>>
>>>
>>> -- Ty Ford's equipment reviews, audio samples, rates and other audiocentric
>>> stuff are at www.tyford.com
>>
>>
>> Ty, we always talk in terms of lines.
>>
>> Thus 720 anything (for example, 720p) refers to a progressive 1280
>> pixel wide by 720 line high frame.
>>
>> Similarly, 1080 anything (for example, 1080i or 1080p) refers to an
>> interlaced or progressive, respectively, 1920 pixel wide by 1080 line
>> high frame.
>>
>> NTSC DV has a frame size of 720 pixels wide by 480 lines high
>> interlaced, which would be called 480i, not 720i. If it were
>> progressive instead of interlaced, it would be called 480p, not 720p.
>>
>> Clear?
>>
>>
>
>Thanks Frank.
You're quite welcome.
>So it's the number of lines that stack vertically that defines
>the resolution.
Well, it's just a convention that the terms 720x and 1080x refer to
the number of scan lines in the frame, that's all.
Personally, I usually try to avoid the use of the term resolution,
especially when used out of context, since it seems to mean so
different things to different people.
On the acquisition side of things, for example, a $400 camcorder with
a 1/6" imaging device will certainly be likely to produce images with
a lower perceived visual resolution than a $40,000 camcorder with a
2/3" imaging device even if it were the 480i composite baseband video
output of both camcorders that was being compared.
Of course, even this assumes that the display device (television
monitor) being used in the comparison isn't a limiting factor. I'm not
certain, for example, that I'd perceive much difference if the display
was a 20-year-old Radio Shack 12-inch black-and-white television.
OTOH, if the display device being used was a Sony BVM-series monitor
or even an old Tektronix television display, I would be inclined to
think that the difference in perceived resolution would be immediately
apparent to even the untrained eye.
>The other number tells you how wide the picture is, as in
>4:3, 16:9?
In any digital video format, and this includes Web formats as well and
not just those intended for television viewing, knowing the number of
pixels per line and the number of lines allows one to determine the
aspect ratio of the frame, either a conventional 4:3 or a widescreen
16:9.
Note that all high definition formats, the two most commonly used of
which are 720p and 1080i, have a 16:9 aspect ratio.
>Regards,
And to you, sir.
>Ty Ford
--
Frank, Independent Consultant, New York, NY
[Please remove 'nojunkmail.' from address to reply via e-mail.]
Read Frank's thoughts on HDV at http://www.humanvalues.net/hdv/
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