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GH2 in 24p: noticeable "strobe effect" with any motion in frame?
  • 259 Replies sorted by
  • @bwhitz I see your point. What about this, however?

    http://www.personal-view.com/talks/discussion/comment/8687#Comment_8687

    "I asked one of the guys from Universal to come take a look at it. He agreed it looked terrible." The way I understand it, he says GH2 motion looked bad comparing to film, if we take that as a reference point (I see that whatever else I refer to here, is getting rather strong reactions, so let's try old media, eh!)

  • @mo7ies So this thread is really nothing more than rehashed rumor-mongering? Your evidence is a second-hand account of what "one of the guys from Universal" said about the subjective results of a completely undocumented workflow that produced a Blu-ray rendering that no one here has ever seen? Here's what @Ian_T had to say about that in the same thread you linked, and I agree with him completely:

    "...um...is it me or does it seem strange that all of these claims of judder don't have any accompanying videos for us to look at? I sincerily have no idea what Dalefpf is talking about. I've heard of these judder claims before with the GH-1. But I've yet to see someone show an example of this "judder" (that is supposedly different from any every other 24p camera). "

  • @LPowell no need to be condescending here, pal. So you had a little back-and-forth with Driftwood, and now you are fuming on him and everyone else, I see it from other threads I'm following. Tone it down, my friend - you are being both unfair, factually incorrect, and too personal.

    My thread is based on my own observations, and I have researched personal-view and other resources before posting here. I also did post a link to the video that illustrates one of the cases, earlier in this thread, together with the "cure" - longer motion blur.

  • @bwhitz

    @mo7ies said

    not enough bandwidth to record enough data when some motion is in frame

    Which I am prepared to accept as part of the general "failure to compress" problem which may or may not apply to strobing. Lots of busy scenes (like analogue TV noise) fail to compress, whether it's issues of codec, processor speed, card writing, de-compression and bandwidth etc. There could be just one bottleneck anywhere - or even a combination of several.

  • Well, @bwhitz got me thinking. Maybe in fact GH2 does record a very sharp video with enough bandwidth to also produce rather low-blur motion. Question is, what is considered visually pleasant? To me, "strobe effect" in place of the expected smooth motion is Not pleasant. I have not worked with Alexa or RED personally, so can't compare. But I did work with 7D extensively, and its motion was never objectionable.

    Now, if @bwhitz is right, maybe 7D's 24p motion is better because it is simply not sharp enough to begin with, plus its codec is rather inferior.

    Then like @Roberto pointed out, most likely there's a combination of factors with GH2. For example, stock 14-42mm lens may exaggerate the motion artifacts by forcing its own over-sharpening algorithm.

    Well, at this point, whatever is the cause, if I shoot 24H at 1/30 shutter, the annoying Orange... err.. motion :) is fixed. If I shoot fast sports, 1/30 feels a tiny bit long on blur, BUT nowhere near as objectionable IMHO as a stuttering look at 1/50.

  • claims of judder don't have any accompanying videos for us to look at

    Yep, talk is indeed cheap. post some samples, to accompany claims, please!

    Until such time, going by @Astro's sample of 1, I hereby find all stuttering video to show measurably less motion-blur than the stated shutter speed should be producing. ;-)

  • @bwhitz

    Please come on. I've been working with Alexa and RED many times. Have done fast dollies where in front of a frame there is lots of vertical objects and we did not use 60fps. Here is picture attached. That's from a dolly track shot, with RED. No strobing, no problem. Theres no irony here. You are terribly wrong if you think that all Alexa and Red material in 24p should have strobing effect. It's about shutter speed. And @Roberto is right about motion blur. You are right that even RED and Alexa has it limitations. Strobing will come out using those cameras if you have, lets say, fast pan and lots of thin vertical lines. But I've done shooting with GH2 hundreds of minutes. I've shot in all shutter speeds there is. I've used 1/25 shutter speed and took a handheld shot with a little movement and there it is. Strobing. At this moment, GH2 generates strobing too easily.

    All I wish, is to look this problem through. Without arguing. I'm not expecting to have same quality in motion as Alexa, but if there is something to do to get better and less strobing shots - great.

    @LPowell I'll download your latest and take a look.

    Best, misterj

    TheHunt_lintsi10.jpg
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  • I did really quick test with @LPowell latest hack. I'm not sure is this the right place to put material for You guys, but here is the one picture from FCP X. I don't have best monitors and videocard at home, but my 1st feel is that I really like, how @LPowell's latest hack captures motion. Specially in 1/25 shutter speed.

    So this shot was f 6.3, shutter 25, ISO 200. It's 24H and kit lens 14-42. Jpg is exported from timeline. I did variation of same kind of movement with shutter speeds of 25, 30, 40 and 50. So @Roberto or anyone else, tell me, if You want to check those.

    Lpowell-test.jpg
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  • @MisterJ Yes, that pic shows the right amount of blur to produce smooth motion. I'm expecting your others are about right, too.

    I'm really more interested in something quantifiable - if possible to reliably produce stuttering video. On my own I can only test a few targeted samples. I keep wondering if there's any benchmark we can all test...

    how about..

    Freight trains often carry universal-standard shipping containers. Where I live we get long trains, (4 km!), moving at a limited speed through town.

    Instead of trying to pan, maybe I'll see if the contrasting vertical flutes on the sides of moving containers can produce stutter.

    Best of all, it's quantifiable:

    • The speed that matters is the movement across the field of view, not the Km/hour. The passage of a given point on a container - say, from left to right of the picture - can be accurately counted by the number of frames;
    • A train is unlikely to make any sudden irregular movement, accelerate or slow down.
    • A train takes long enough to pass by for a number of takes at different shutter speeds.

    At present, I'm inclined to use firmware 1.1 (no hack) and the lenses I have. (14mm pancake might work with such a big subject).

  • @MisterJ

    That's from a dolly track shot, with RED. No strobing, no problem. Theres no irony here.

    I was just saying it was ironic because you were saying that the studdering and panning of the motion was restricting your shot choices... yet this is exactly what you would run into when shooting the holly-grail of "cinematic" formats... film.

    Film at 24fps, if you talk to a DP or operator, has well know pan/dolly speeds that they won't exceed for those exact reasons. 24fps just has allot of judder.

    Don't know why your Red footage doesn't have the same judder though? I've been on Red shoots where the instructions have clearly been... "push it a bit slower, we're shooting 24 frames". The motion of Red looks identical to the Intra-GH2 patches. Maybe you are running into a glitch or something...?

    So this shot was f 6.3, shutter 25, ISO 200. It's 24H and kit lens 14-42

    Might be the lens actually. Some people have reported that the Panny lenses cause excessive sharpening and detail judder... do you have other manual non-panasonic lenses to throw on there?

    @mo7ies

    "I asked one of the guys from Universal to come take a look at it. He agreed it looked terrible."

    Dunno. Wasn't there. It was either a vindictive statement... or they're running into the stock lens glitching that I've mentioned and heard of.

    I'm just thinking that it must be a glitch or something you guys are running into. After all the great projects and footage... and the outstanding performance in the Zacuto shootout from the Quantum patches... other people would have said something. Colt Seman and those guys have been using the GH2 for tons of automotive and fast action stuff. We would know by now, as a community, if there were any real problems with motion.

  • BTW, make sure your OIS is off when panning – it might introduce judder.

  • @nomad

    BTW, make sure your OIS is off when panning – it might introduce judder.

    Yes, good call. I think a few people have mentioned that this was causing problems. This might be the lens glitch others have mentioned.

  • Film at 24fps, if you talk to a DP or operator, has well know pan/dolly speeds that they won't exceed for those exact reasons.

    I shoot film, 35mm and 16. The faster I pan, the better it blurs at 180 degree shutter. A zip-pan looks smooth on film. It also looks fine on a GH2:

    image

    We all do the still/pan/stop routine, intuitively:

    Press shutter, and ONE, two, three, then pan [Object frame right moves to frame centre left slowly] and ONE, two, three four five, slow then stop] and still ONE two, three - and CUT.

    In narrative film, a pan without camera following a central figure is a rare animal.

    The limitations to speed are more often aesthetic. When panning you need to know why. In whose time is this shot I'm about to take? For example:


    Scene 4_________ Interior________Day_________Gary's Room_________ Scene 4

    Gary returns home to find his home ransacked. He looks around, afraid the burglar could be waiting behind any door....


    This is one of those rare circumstances where a DOP might choose a slow pan.

    Using film, you can get a smooth shot of what Gary sees as he looks around the room. The audience have no central figure moving around to distract them. Their eyes will follow every bit of this POV shot, scrutinizing everything they see.

    A GH2 may give you problems here.

    Note: Luckily, you can apply motion-blur in post here, because the whole scene is moving, so everything gets a one-click blur. If you had someone walking around, [ie static within the frame], you'd have your work cut out for you trying not to blur them too, along with the moving furniture.

  • Luckily, you can apply motion-blur in post here, because the whole scene is moving, so everything gets a one-click blur.

    Actually, with After Effects plugins (and I'm sure in other compositing software, too), one can force motion blur proportional to the actual amount of pixel movement in-frame. So post-production motion blur on the person you are tracking should look same as in-camera, provided you used correct AE plugin/settings. So it's better than you thought :)

    But, as always, it'd be preferable to nail the motion blur in-camera.

    With GH2, I now think it makes sense to learn how motion is represented with different lenses/focal distances/scene setups, and in fact employ different shutter speeds on each shot.

  • after quantum v9 was released until date none of the patches has such strobe effect at all....for example quantum 9 x orion sedna canis cluster all these are somewhere beyond this kind of effects.... may be its lens...

  • @mo7ies I suppose you are referring to RSMB by RE:VisionFX. It works quite nice in many cases, but it's not a cure-all solution for insufficient motion blur, has difficulties separating the edges of moving objects for example.

  • difficulties separating the edges of moving objects

    That's a big problem. Pans with no subject are rare opportunities to use full motion-blur of everything you see. But much more common are tracking shots: blurring the nearby bushes as they scoot by is easy enough. But the buildings further behind the bushes will be revealed by parallax, moving slower; the mountains will hardly move at all, while the sun will stay rock still. I would get annoyed with any software which wanted to motion-blur my mountains & sun.

  • I just got sent a link to a GH2 vimeo which stutters badly using my PC. If this stutters for others, too, then maybe I can download the original and see what's going on. (Tho' it could be just my low-powered notebook's graphics causing stutter..) Funny, the writer didn't notice, saying "This video .. not mine sadly shows without doubt the GH2 still has the best PQ of any cam/ DSLR under $4000"

  • @roberto before you analyse, do you know the precise shutter speed and frame rate that the video was captured at?

  • @itimjim

    No idea. I can calculate actual shutter rate -frame rate should be obvious if it hasn't been modified. If it's stuttering video I'll contact the person who posted it & ask. How does it look you? (apart from being fantastic).

  • @roberto I'm still trying to understand what you (and everyone else) means by stutter, but I think I'm getting there.

    I was previous of the understanding that you meant there's a noticeable shift in cadence, like a jump from a poor pull down, there's none of that in there.

    If you're on about a little consistent frame cadence on horizontal (and sometimes vertical) pans, well that's intra-frame 24p for you. With the motion in that piece you linked to, if 24p cadence is a problem for your viewer, then you'd be nuts to shoot it that way. I don't see why that piece would need, or even want 24p...it's not cinema. But, I suppose if you're hooked on the detail of the hack, and you're unwilling to go HBR/720p, you're then at the mercy of a 24p intra-frame motion capture. But, having said that, I don't think it's as bad as some people make it out. It really doesn't put me off watching something. As someone said before though, it's like the DLP/LCD discussions that rage on. I see the rainbow effect, but it doesn't put me off so much, if at all.

    I realise I've just opened the door to the Red/Alexa boys (of which I have zero experience) to say the above would look fine at 24p on them. All I know is that if the above was shot on film, with that range of motion, it would display a very similar motion capture character (rolling shutter aside).

    Personally, I'm 'almost' desensitised to 24p cadence, as I'm just so used to it from the movies.

  • I am on my laptop and cannot see GH2 stuttering in the video above.

    Moreover, I cannot see stuttering in the following video someone posted on Driftwood's thread - however it does display classic GH2 stuttering on my production machine with high-end video card and monitor!

    So here we go, it does depend on the playback device...

  • @mo7ies Thanks, wrong call I'm afraid. It was as if Vimeo might have sensed my slow internet connection and dropped back to 14fps (now that would be a clever trick) I really did notice a flicker when the guy swings the golf club - but then they might well have chosen a sporty, too-high shutter rate just for that shot.

  • @itimjim

    I'm 'almost' desensitised to 24p cadence, as I'm just so used to it from the movies.

    Me too. I think we all are, if left alone - and there's a danger in a videographer becoming too sensitised to something which viewers don't see. (Usually there's something better to watch than the stuttering background; remember the "gorilla on the basketball field video?")

    One medical definition for the "palpitations" which patients sometimes complain about is given as, "an awareness of one's heart beating." Getting over the palpitations is getting used to the heart beating.

    Maybe a healthy balance regarding learning to live with 24P stutter is knowing to deal with it only when it becomes an issue to the viewers.

  • A question for everyone insisting that the judder is inherent in all GH2 footage: do you watch it on a monitor with a refresh rate that is a multiple of 23.98?