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March 24th, 2009, 03:57 AM | #61 |
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Rolling-Shutter Artifacts with XR500
I've just looked at the samples posted from an XR500V and was disappointed in how badly the image fluttered and blurred during panning and when the camera jerked around. I'm surprised that no one else has been discussing this. The same problem exists with the HD video from the Sony HX1 and Canon SX1 digital cameras. They use progressive scan, while the XR500 is an interlaced-scanning model. My Sony HC9 has a CMOS and interlaced-scanning, but shows almost none of these rolling-shutter artifacts. Due to this, I expected that the rolling-shutter problems would be minimal with all interlaced/CMOS models, but that must be a mistaken assumption.
Apparently, the way to avoid the flutter and blur of a rolling-shutter, is to use CCD sensors, which function with global-shutters. The CCD pixels can store their responses and are exposed all at the same instant. The scan then collects the stored responses as it passes each pixel. Since the CMOS pixels can't store responses, their active exposure occurs at the same instant the scan passes them, causing an exposure time-lag between lines that results in the flutter and blur when panning. CMOS sensors can be made with extra transistors on the pixels, which could store their responses and allow the simultaneous exposure of a global-shutter. But, this would reduce the sensing area and dynamic-response. I don't know why the manufacturers ignore these undesirable side-effects of using CMOS sensors on video cameras, but it forces you to avoid panning, unless following a moving subject that stays in the same position in the frame. Why my HC9 avoids this problem so well, I don't know. I don't think my finances are going to be depleted by buying an XR5 model. Here's a link to a good article by Barry Green on the subject of rolling-shutter. Don't miss the link part-way through, to a comment by CMOS designer Jason Rodriguez. There's more links to related articles at the end. http://dvxuser.com/jason/CMOS-CCD/
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March 24th, 2009, 04:30 AM | #62 |
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Many people make the mistake of making comparison while viewing on a computer monitor. Unless you view on a large screen (which is far more revealing), you'll miss the true picture quality differences when comparing any 2 or 3 cams.
Small computer monitors, even a 22", is no way to compare cameras. |
March 24th, 2009, 12:04 PM | #63 |
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my sr 12s pans are just as good as my hc-1 and fx-7 hdv cams they are perfect played direct to tv,some softwares tend to spoil the pans a little compared the hdv pans though ,it would be strange if the new models are worse in this respect.
Last edited by Martyn Hull; March 25th, 2009 at 02:51 AM. |
March 24th, 2009, 01:43 PM | #64 | |
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Keep in mind when checking reviews, samples, and opinions they may have wildly varying accuracy or none whatsoever. For instance the above referenced "reviews" were helpful in GENERAL, but almost worthless because not one single "comparison" shot was shot at the same exact time, with both cameras side by side... at least the Japanese site has undertaken to do their samples that way, and it was helpful in that respect. BUT, I can see that the HF-S with the proper settings can do some serious image quality in low light, the settings make a big difference, but the Japanese samples were probably in "default" mode... "User malfunction" is the technical term for this phenomenon, and it's one reason that taking ANYONE'S "opinion" or posted "evidence" must be done with a grain of salt the size of a battleship... review sites MAY be better, but have typically short "experience spans" with a camera. Your HC9 has all the "RS" issues, guaranteed, as it is a CMOS sensor... so why don't you have the same problems? Because CAMERA TECHNIQUE makes a huge difference when shooting these cameras - you also use an add on stabilizer (clever design BTW, different from mine, but similar concepts), which IMO is a necessity for these small cams to get professional results. CMOS v. CCD has been discussed ad nauseam, regurgitated, spewn about, flame broiled, and lineage disparaged to the point of being absurd. CMOS are the "future" as far as small consumer cams, and Sony has even committed their high end line to the same tech. It's a price/value/cost thing I'm sure, and one day when things (like the new "R" sensor) exit the lab, it's quite possible that CMOS can go global - it's similar to Moore's law (can I make a new law for video and call it "Dave's law"??) where as semiconductors improve, shrink, and improve in manufacturing efficiency and overall speed, you get more bang for the buck, and better performance. Just imagine for a minute trying to edit even HDV on a 10 year old computer... that's pretty close to what the first HC1 user faced, and now NO ONE disputes being able to edit HDV footage with reasonable results (though some still fail epic-ly at it...) You shoot with the best camera you can afford that meets your needs/objectives. I've been very happy with AVCHD/tapeless, and don't plan on going back. I wasn't too sure about the XR5xx, BUT I'm convinced after seeing several reviews now that the low light by itself is worth the price of entry, and while I wish for other features, I think I could find the XR500 useful as it is. I will say that the HF-S looked quite good the way the reviewers set it up (cinemode seems to help low light a LOT), and it's a tempting camera, what a great time to be camera debating once again! EITHER the XR500/520 or the HF-S10/100 should be a knockout camera (and yes, both use CMOS). The Panasonic results were a bit disappointing, all things considered, I'm waiting for them to come in with a category killer, the HMC150 (with CCDs) is doing quite well among wedding/event guys, with NO competitors, so Panasonic CAN keep up if they want to. As with many things, if the user learns to use the equipment properly, you can get pretty good results - or you can find fault with every little thing and sit around whining rather than DOING. RS is a "big deal" the first time you see the "partial flash exposure", the bendy verticals and the rubbery jello from whip pans or bouncing... Operator technique takes 2 out of 3 of these OUT of the equation, the first you just have to get used to, and the main problem is for wedding/event video that you want to slo-mo. Other than that, it's a annoyance, as were flashes and smear with CCD (different annoyance, but STILL ANNOYING!). If you're happy with the HC9 (which is the last of the tape based consumer cams I suspect, and now at least two generations back tech wise), you won't find any disappointment with it's later replacements, at least not as far as RS goes - I suspect the XR's may have some improvement in that area, as did the SR11/12 & CX12's... yes there's RS, so learn to stabilize the cam and control what you do with it, and you won't really be worrying about the "technical flaws". |
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March 24th, 2009, 02:39 PM | #65 |
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The XR500 Samples Were on Post #26 in this Thread
Dave, you are a born salesman and put on a very good argument about the reasons and remedies for the rolling-shutter artifacts of the XR500/520. It's true that the poster of the XR500 samples on this thread swung and jerked the camera too fast. But, every time the camera moved, the flutter and blur appeared and regardless of technique, that shows a severe limitation on shooting options. I'll take the rather easily-avoided artifacts of CCDs anytime, rather than the CMOS problems. There has to be more to these artifacts than just the fact that certain cameras have CMOS sensors. Some of them seem to avoid the artifacts more than others.
It's true that the software playing programs can make the artifacts worse. Before I updated my computer's CoDecs with a download of the K-Lite CoDec Pack, I was seeing these problems about twice as severly and my players previously had some trouble showing AVC video smoothly. Now, Windows Media Player 11 and MPC handle them without a flaw, except if the rolling-shutter flutter and blur exists, they will still show it to an unacceptable degree. I already have one little camcorder, the Webbie HD, that has to be used very carefully, to avoid the artifacts. I will certainly take a Pro Duo card to a local dealer, when an XR5 model is in stock and use a demonstrator camera to see what it will do for me. I'll deliberately try to show bad artifacts and then do the opposite and shoot good video. We'll see how that works out, after I edit and produce some finished pieces from the footage. However, when I pan my HC9 around fairly fast, I see very little blur and flutter and often, none at all. Watch this HC9 video I posted on Flickr, where I pan around in an almost 360-degree arc. It's fast enough to cause rolling-shutter effects in some other CMOS cameras: http://www.vimeo.com/1998054 I'd really like to get to the bottom of this great difference in results from the various CMOS camcorders and digital cameras I mentioned in a previous message. When I play my Webbie HD directly over an analog HD-component connection to my HDTV set, the video looks very good, with few of the artifacts I see on my progressive LCD computer screen.
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March 24th, 2009, 04:02 PM | #66 |
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It appears that Dave Blackhurst and recently Wacharapong Chiowanich have seen video samples from the TM300/HS300 that maybe I haven’t seen yet. Again, which ones? I hope it's not from the Watch.Impress review because I don’t think they did a good job.
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March 24th, 2009, 05:10 PM | #67 | |
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Even the HMC150 is getting hit for being a bit soft at the highest resolutions, being best at 720 rather than 1080, because of the way Panasonic is doing their sensors. Not saying it doesn't work, and I'd probably go for a HMC150 over anything else in it's price range for a number of reasons were I buying... but you'd think they could bump things up a notch and be more competitive. |
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March 24th, 2009, 06:10 PM | #68 |
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I’m not even going to comment on InfoSync's conclusion because it seams too biased but where in Camcorderinfo’s HD2000 review did it got compared to either the TM300 or the HS300?
So what’s wrong with ¼” chips with a native resolution of 1920x1080 each? The chips are the exact same specs as the HPX300. I’d say it’s just a smaller version. That’s more than the V1u which also has 1/4" chips. If their really is something wrong with the camcorder then it’s definitely not the chips. I think without many native samples to view, it’s being treated unfairly. |
March 24th, 2009, 06:17 PM | #69 | |
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You note that even your Webbie with low bitrate looks a bit bad on your computer screen, but not on HDTV... I'll bet that the XR's will be significantly better than the Webbie... It's not a matter of being a "salesman", it's just actual experience with these cameras, and I went through the early adopter headaches with HDV (HC1). You need a reasonably fast computer to work well with AVCHD, and I still feel that the editors and codecs could use some tweaking... BUT there's not a RS issue if you handle the camera and video post properly. I can't say why some people are having more issues than others, but that's life on the bleeding edge. I had hoped to see more refinement in the AVCHD editing/processing department by now, but with the economy, perhaps it's taking a bit longer. With the number of these cameras selling to the general public, you can bet the kinks WILL get ironed out sooner or later. I can tell you with Sony Vegas Pro, the preview window becomes horribly blurred and smeared as soon as I go past the lower settings for the preview window - motion trails are unbearable, and skew looks worse - dropping to a lower quality level (that is plenty good for editing) all the artifacts disappear, and I mean completely GONE... and I don't have problems with my rendered results either. I don't know what it is about AVCHD that seems to be prone to ghosting/motion artifacts under some circumstances, but it's not something that should make your output look bad from everything I've shot. Evidently it's pretty easy to goof up though, as many of the web videos I've seen indicate. If you 've got .mts playing smoothly, download the raw clips before you jump to a conclusion. Remember too that your Webbie tops at 6-8MBps (allowing for VBR), and the XR5xx will top out at around 16-18 (maybe higher, again allowing for vbr), and that 2-3x increase in bits flowing through the pipe will tax your computer - maybe a lot. As an example, I was experimenting with encoding BR to a regular DVD for playback on a BR player... encoding to 8MBps playback was fine but looked pretty bad from the low bit rate, and when I tried the template max setting of 25MBps, it jerked, shuddered and choked... finally went to around 17MBps, and got good playback AND good image quality. The lesson is that more bits take more horsepower to push about effectively and smoothly, and sometimes you have to tweak settings to get usable results. Of course, going direct into a HDTV from the camera is a fairly decent test, and you generally won't get the problems there. |
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March 24th, 2009, 07:46 PM | #70 | |
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My mistake on the CCI review - they compare a Panasonic model, for some reason I thought it was the latest release... and that camera didn't perform badly, just not as good as the Canon and Sony. It will be interesting to see a full review from a couple other places. In theory, 3 x 1/4" chips ought to be fairly good. Perhaps as more info comes out, the camera will shine, but Panasonic has been bringing up the rear for a while - when you consider the price points, they need to deliver the picture quality, not just the excellent ergonomics and controls. And in some respects the good layout and controls might trump minor defects in image quality, depending on the user needs. I've owned some Panasonics and really liked them A LOT, so I certainly keep an eye on what they are doing, but they have yet to convince me that there's a reason to go with them again... |
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March 24th, 2009, 08:26 PM | #71 |
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Camcorderinfo tested the Sanyo against the cheapest Panasonic camcorder for this year and the TM300/HS300 is the most expensive which they haven’t even reviewed yet. I’m looking forward to that one even though I don’t agree with everything they say but I do trust them a little bit more than InfoSync.
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March 25th, 2009, 12:33 AM | #72 |
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It's going to be an interesting 3 way shootout that's for sure - clearly they have hands on a HF-S, and should have an XR5xx... the Panny should be in the mix.
I don't "trust" any of the review sites per se, I try to see what sort of results are common between them, and based upon my own experience with past cameras and reviews, I can get a pretty good idea what to expect. The personal "reviews" here also count for quite a bit in my book, as everyone here is WAY more picky and analytical than the typical "reviewer", and so it's hard for a camera (or a review site!) to get away with much! |
March 28th, 2009, 02:44 AM | #73 |
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Test on Vimeo: Sony XR520 vs Canon HF S10 in low light
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March 28th, 2009, 06:24 PM | #74 |
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It certainly appears that with proper settings, the HF-S will do quite nicely in low light, although from the posted samples I've looked at I think I like the XR a little bit better (just a tad less noise, and crisper blacks), but looks like finally the low light/hi def barrier is falling in the consumer end. I still am amazed by how good these little monsters are getting for the price! The SR11 has been a great little camera all around, the XR does look like it might justify the upgrade.
What a tough choice of cameras! If Sony doesn't refresh the CX12 with the "R" sensor or come up with a DSLR with video that makes sense, might just have to see about getting an HF-S for manual control too! |
March 29th, 2009, 06:50 AM | #75 |
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New Test: Sony XR520 and Canon HF S10 in day light
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