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October 25th, 2003, 03:34 PM | #1 |
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DVX lines of resolution?
I tried searching for this topic all over yahoo and this forum but keep hearing different answers. I've heard some people say 380, some people say 500. How many lines does the DVX (NTSC) put out? Thanks.
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October 25th, 2003, 03:39 PM | #2 |
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Re: "How many lines does the DVX put out?"
You mean, the playback? E-mail Panasonic outside of N.A. They'll tell you. |
October 25th, 2003, 11:47 PM | #3 |
Barry Wan Kenobi
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NTSC interlaced cameras are limited to about 360 lines of resolution, due to the Kell factor and anti-flicker filters which are designed to overcome the limitations of an interlaced display system. Put the DVX in interlaced mode (60i) and you'll get about the max, 360 lines.
Switch it into progressive mode, engage the "thin" line detail feature, and you'll get a full 480 lines. The lens & recording system are sharp enough to resolve a different line on every pixel. No other DV-format camera comes close. For pictures of various cameras shooting resolution charts, check out: http://www.bealecorner.com/trv900/cats/cats.html (especially pay attention to the progressive image from the DVX vs. the interlaced image, and look at the vertical resolution as measured by the horizontal wedges, and you'll see the incredible difference). Note: this measure of resolution is on actual countable pixels, not "TV Lines" of resolution. As far as "TV Lines" goes, the DVX peaks the meter for DV-format cameras: 540 lines. |
October 26th, 2003, 11:16 AM | #4 |
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<<<--
As far as "TV Lines" goes, the DVX peaks the meter for DV-format cameras: 540 lines. -->>> I can understand why analog out from any dv camera should be limited to 525 lines or so, but why can't a dv camera really do 720 lines on the digital output? Many of the high priced dv cameras (like Sony 570) claim 800 lines internally, and have ccds which support the requisite number of pikels to handle this. What is the point of dumbing down the output digitally? |
October 26th, 2003, 12:39 PM | #5 |
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Thanks Barry! Exactly what I was looking for
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October 26th, 2003, 01:27 PM | #6 |
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Marc,
It isn't a matter of "dumbing" down dv. The CCD itself can only contain a certain number of pixels per line. Adding more adds cost for the ccd and, therefore, the camera. Not to mention the fact that sending more pixels out on a line may require higher speed circuitry to handle that. Secondly, most transmission systems and TV receivers cannot display 800 or more pixels on a line, particularly in ntsc format. |
October 26th, 2003, 04:23 PM | #7 |
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<<<-- Originally posted by Marc Young :
I can understand why analog out from any dv camera should be limited to 525 lines or so, but why can't a dv camera really do 720 lines on the digital output? -->>> Because "TV Lines" aren't counted that way. TV lines of resolution are figured as the maximum horizontal resolution possible, when considered in the context of the maximum vertical resolution. So TV lines is the # of horizontal lines possible IN A SQUARE PATCH of the television screen. And since the screen is shaped 4:3, that means that you only get to count the lines in 3/4 of the horizontal area of the screen. And 3/4 of 720 is... 540. Which is why the absolute maximum resoltion possible in a DV camera is 540 "TV Lines" of resolution. |
October 26th, 2003, 04:30 PM | #8 |
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I've contacted Panasonic about what the playback is, on a waveform monitor. I figure it's at least 500 lines.
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October 29th, 2003, 05:06 PM | #9 |
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<<<-- Originally posted by Barry Green :
TV lines of resolution are figured as the maximum horizontal resolution possible, when considered in the context of the maximum vertical resolution. So TV lines is the # of horizontal lines possible IN A SQUARE PATCH of the television screen. And since the screen is shaped 4:3, that means that you only get to count the lines in 3/4 of the horizontal area of the screen. And 3/4 of 720 is... 540. Which is why the absolute maximum resoltion possible in a DV camera is 540 "TV Lines" of resolution. -->>> Ah, but why limit it to a 4:3 screen, when many cameras are starting to offer 16x9? The dv format supports 720 lines, at 13.5 MHz sampling (I think). As for display, when you author to dvd, you can retain the 720 pixel resolution (if it is there originally) and any decent rear projection tv will allow you to display it in 16x9 wide mode vs. 4x3 squeeze mode. Even in squeeze mode, the good tv sets reclock at more than 540 pixels (across). The highend progressive dvd players output at 54 or 108 MHz. Has anyone measured the real resolution out of one of the professional camcorders with 800 line ccds? Is Sony's claim all hype? |
October 29th, 2003, 07:40 PM | #10 |
Barry Wan Kenobi
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The very definition of the term "TV Lines" requires that they be measured in a square patch.
When a manufacturer brags about 700 lines or 800 lines, etc., they're talking about how much resolution the *camera head* can resolve. That's not how much gets recorded to tape, because the tape mechanism (whether DV, DVCPRO50, DigiBeta, any standard-def format) limits the recording to 540 TV Lines. You will never encounter a standard-def camera that records more than 540 lines, regardless of what the camera head claims to resolve. (but a sharper camera head definitely leads to a better picture being recorded in those 540 lines!) Ideally a new metaphor is necessary, because "TV Lines" is just confusing. Should be measured on something like line pairs per millimeter, like film is. |
October 29th, 2003, 08:03 PM | #11 |
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I think JVC's Streamcorder can resolve more resolution than the DVX's......700+ lines is within it's capabilities- but the DV format can only record 540.....so I think the JVC is our mini-DV champ!
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October 29th, 2003, 09:41 PM | #12 |
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October 29th, 2003, 09:45 PM | #13 |
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Here we go again
http://www.dvfreak.com/res.htm Almost all miniDV cams capture more "lines" than what they can play back. Pana claims over 1500 lines for the MX500, but only plays back 500. I presume the Streamer's playback is about 500 lines, but certainly not over 540. Even the DSR300 only plays back 510 lines (DV Mag. wave-form test). Claims are claims, we can only take them with a grain of salt. |
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