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_Vertical_ resolution: SD vs. HDV cam?
Question: Is the vertical resolution of the Panasonic AJ-SPX800 cam’s SD similar to the vertical res of (for example) a Sony Z1 HDV cam’s 1080i HDV after deinterlacing?
The specs for the SPX800 say: “Horizontal Resolution: 750 TV lines at center, standard; Vertical Resolution: NTSC: 400/450 lines (super V), PAL: 450/500 lines (super V).”
https://tinyurl.com/dbzfn(Are these values true for when the cam is in progressive 24p/30p mode?)
I believe video recorded by the Z1 in HDV mode and deinterlaced by good software/hardware results in approx. 550 vertical lines of res.?
I realize these are very different cams with very different configurations & prices (the AJ-SPX800 list price is about 4 times the Z1’s), but I’m curious if in this respect if the vertical resolution of their video in _progressive_ form is roughly similar. Or am I misunderstanding what these specs mean?
Comments welcome.
All the best,
– Peter
Just a friendly reminder to all: Please consider filling-in your COW user profile information so we have a better idea who you are, where you’re from, and so forth. It’s the friendly thing to do. Thanks!
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10 Replies
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The interlaced rez of the Z1 is about 800×800, deinterlace that and you’re somewhere between 400 and 800 vertical rez depending upon movement. In the CF25 or CF30 mode, V rez will be stuck at 400, but that’s really made up of 540 lines interpolated back up to 1080. The actual rez is lower than the pixel resolution because it’s a sampled system that needs pre-filtering to stop aliassing, like all cameras. Of course, the CF24 mode is an abomination and should not be used unless you want a really cheesy film effect. (again, half vertical rez and bad motion stutter and the visual appearance of double shutter speed – ouch).
The SPX800 probably has a “thick” or “think” mode for progressive. That means that you can turn on or off the filter that is there to stop line twitter on interlaced display of the video. That’s still needed even if you put progressive video on a interlaced TV, but if you’re going out to film or to uprez to HD, you might want this filter turned off for more real rez captured.
So what’s the actual rez of the SPX800?? Probably about 500×400 or 500×450 depending upon choice of filter, and that’s in progressive mode. Also, each one of those pixels is compressed less, you’ve got a bigger CCD and probably a better lens too.
That means that if you stick the SPX800 in 24p or 30p mode, and stick the resulting video into a broadcast quality up-converter, you’ll end up with a better image than off the Z1, but you’d have paid more for that image. You’d have much superior 24p mode, if that’s what you want too. Sony were claiming that the video from their DSR570 uprezzed is better than the Z1, so I’d expect that the SPX800 or SDX900 would be better still as DVCPro50 is much better than DVCAM.
Graeme
– http://www.nattress.com – Film Effects for FCP
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Thanks for the info, Graeme. Much appreciated.
Yes, the SPX800 definitely costs w-a-y more than a Z1, HD100 or other “current” HDV cams. But since I’m thinking of buying a SPX800, it’s good to know its upconverts to HD have some chance of “competing” with good HDV cams at least on visual terms, if not price-wise.
(My initial use of the SPX800 will be for standard definiton projects, in all frame rates, and interlaced & progressive. But it’s reassuring to hear its DVCPRO-50 24p & 30p recordings can be cleanly upconverted to HD. I’ve seen Terranex upconverts of 60i DigiBeta to HDCAM on an good HD projector & it looked marvelous.)
Thanks again, Graeme. If anyone has related comments I’d like to hear them, too.
All the best,
– Peter
Just a friendly reminder to all: Please consider filling-in your COW user profile information so we have a better idea who you are, where you’re from, and so forth. It’s the friendly thing to do. Thanks!
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What I’m wondering is what the DVCPro50 mode on the HVX200 looks like, and if that uprezzes to HD and looks better than recording in the more compressed DVCProHD mode or not?? Could be a very interesting comparison….
Graeme
– http://www.nattress.com – Film Effects for FCP
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Aloha Graeme,
The following is totally non-scientific, but has some bearing on the conversation. I’ve read several people saying up-rezzing 4:2:2 SD footage might result in better pictures than a Z1 produces. We have a D9 DY90U camera (nearly identical to DVCPRO50) and an FX-1. Of course the D9 camera is interlaced, but so is the FX1. Playing both of these cameras on a Dell 24″ 1920×1080 mode monitor, there is absolutely no comparison.
The D9 image is very fuzzy and looks just like a low resolution image blown up several times. The FX-1 image is so clean (even reds) that there is no way that I think you could ever convert the D9 image to anything close to the FX-1 image (this also pains me because we have a heck of a lot of stock footage shot on the D9 camera).
While the FX-1 certainly has motion problems for us, even those shots look much better than comparable shots blown up from the D9 camera. A 480p image will probably blow up better, but I don’t think it will approach even the Sony. The new JVC and Panasonic entries appear to be much better, but only time will tell.
We will probably have a real of the D9 stuff upconverted at the place we vault our footage, but I don’t hold out much hope. We’re selling the D9 gear and moving on, probably to the new Panasonic if they figure out a hard drive capture solution so we can do long form shooting.
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It all depends on how the SD footage is upconverted – there are good upconverters, medium ones, and bad ones. I’m working on a software up-converter that I hope (and early tests show) should be in the “superb” category. If you ever get to see a Terranex or Snell and Wilcox upconverter in action, I reckon you might find it hard to tell the difference between good SD and HDV. Sony were telling us at their demo of the Z1 in Ottawa that upconverted DSR570 footage looked better than the Z1, for instance.
Graeme
– http://www.nattress.com – Film Effects for FCP
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Aloha Graeme,
If what Sony says is true, then I’ll sleep a lot easier. We do all our transfers for stock at Point360 in Hollywood and they’ve got all the latest conversion gear. We’ve had a few transfers done for Discovery etc. and they seemed to be happy, but we’ve never seen the results as we don’t have anything that can playback HDCAM. Not too hopeful about getting an HDV copy out of Point360 until someone makes a HDV deck with HDSDI.
Aloha,
Ken
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I think a few companies are now coming to market with Firewire to HD SDI boxes for the Sony HDV, but I still think it’s amiss of Sony to call the deck “pro” and not have pro connectors on it – whatever were they thinking?
Graeme
– http://www.nattress.com – Film Effects for FCP
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Fast $$$ maybe?
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We have developed a film transfer here at the our research institute which is using Photo Zoom Pro (formerly called S-Spline) and we get very good results from SD footage. Many cinema people don’t even believe it was shot on video.
But I hope we’ll see something even better from Graeme.
Regards,
Uli
Author of “DVDs gestalten und produzieren”, a book on professional DVD-authoring in German.
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