>it's best to test it on m43 lenses as they tend to give more aliasing.
yes, that's what I meant, run a test with one of those lenses against a low contrast, soft, old lens and see if it makes a difference to motion. I don't have a low contrast lens, else I'd do it myself.
@_gl I Yes a diffusion filter tames excessive sharpness... usually aliasing. That's a good thing while the filter retains non-aliased good details.
24p might introduce more motion aliasing. A diffusion filter reduces such aliasing. That was lpowell's advice on aliasing topic thread from last year and I got a diffusion filter.
If sharpness is the issue than contrast plays a role too. The B&W video Ian-T posted as an example has high contrast, and high contrast strongly improves the 'perceived' sharpness. If we're on the right track, old soft and low contrast lenses should decrease the effect. If someone who owns such lenses (Canon FD maybe) could run a test against a kit lens or other sharp contrasty lens we might see if it really makes a difference.
Blurring in post was my first suggestion which he said would be a start. From what I could understand was that it was something that the camera is doing that was screwing up the image as it's being recorded. Not sure what the difference would be. Maybe someone here would know. I'm going to pick his brain later in the week. Didn't want to annoy him too much.
@Mark_the_Harp I too have noticed what is being called judder (a staccato-like pattern on sharp edges and and regions of high contrast) in my footage with pan, tilt, and dolly movements. I believe sharpening contributes to the effect, for I have several pan and dolly shots with areas of soft focus that do not judder. It's only when the shot comes into focus does the judder occur. It also depends on the speed of the camera movement. Very slow movement does not seem to cause the effect, or at least it is less noticeable.
Shooting handheld reduces the sharpening as well. In smooth @ -2s with .9 ND I've not had much of a juddery stuttery problem in camera (just on my last gen. Imac which can't keep up in FCPX). But yeah, if we could reduce sharpening even more and turn down the ISO it'd be great. That ultra sharp HD look is, IMHO, very unappealing in comparison to film…and to be avoided if you want the cinematic look
@Mark_the_Harp yep if the judder goes away, it's the sharpening/LCD issue. I never see my problem on unsharp areas. You can also try just blurring the image a little in post (same deal).
@Dalefpf Thanks for the update. Will be great to see what else he comes up with.
If it is a sharpening issue, what happens if you just shoot a bit out of focus on the GH2? If the judder goes away would that tell us anything at all? And if it doesn't, similarly, would that be revealing? Hell, I'll try it!
Hey guys, I just wanted to update what I was told about GH2 footage I sent out to a friend of mine that does post production work. He works on a bunch of high end films and I think what he says is golden. I actually believe him more than my own eyes. So what he told me is that it is in fact a sharpening issue. At first he agreed with my description about the problem and still thinks there is an " odd feel " to the GH2 24fps. After looking at it frame by frame he decided that the sharpening being done internally was causing the problem and can be perceived differently by different people. Just like some people are annoyed by fluorescent lighting while others are not. Someone mentioned earlier the rainbow effect with DLP projectors which might be the right idea.
I will say that in his first email he said the footage looked slower than 24fps but that was before he looked at it closely. I was told there may be a few things you can do to address this problem and that he will mess around with the footage when he gets some free time. Obviously, being able to reduce the sharpness would help but I'll wait to hear what he says and pass it along. A few other things that can have a negative affect were down rezzing and digital projection can highlight it as well. Their company actually fixed a film from China which had similar problems but for different reasons.
This is still a problem for me and others, I believe. I do think that there is hope in fixing it. Now, I really respect this guy but take it for what its worth. I don't think he spent a ton of time looking into this. It looks like this thread was heading in this direction on it's own anyway.
@bdegazio, yeah, basically the GH2 is just too sharp for it's own good : ). Seriously, it's easy to get addicted to sharpening, I was for a long time, but if you look at most cinema footage it's rarely as sharpened. That's why you don't often notice the LCD strobing there.
Also if you think about it, sharpening doesn't add any new detail (just increases contrast around edges), so there's no point having it burned into the footage when you can do it in post with more control (except for convenience if you don't want to do it in post). Also the extra contrast it creates uses up more bit-rate for no real benefit. And the high-bitrate patches already give you a more detailed image. So it would be great if (eventually) sharpening could be defeated altogether.
I use a three monitor setup with my NLE system. Two LG 20" 1920x1080 computer monitors and also have my 50" Samsung D6300 1080P set hooked up for video preview. Both computer monitors display motion issues. The Samsung TV set looks normal. Do not judge motion on just your computer monitors. I'm not saying this is definitive, but one needs to be aware of this.
This topic seems to be normal for damn near every new video camera that gets released. There's always a discussion on judder and overall motion.
@_gl, I think you;ve hit the nail on the head! Your example with the pixel checkerboard is a fantastic demonstration of the problem. That whacky LCD pulsing is exactly what I've been seeing in the GH2 footage and calling "strobing". It also explains why the problem seems rather worse with the GH2 than with some other DSLRs- because of the GH2's sharpness and detail, the LCD pixels have to pulse that much more.
I agree with you about disabling sharpness in-camera, if possible. Whatever gets us closer to the raw sensor data and bypasses the questionable built-in DSP is an improvement, IMO.
The type of strange strobing I've noticed on my GH2 is due to sharpening, when you're viewing on LCD monitors.
The LCD monitor issue hasn't been mentioned, and isn't widely understood - LCD pixels respond slowly, much slower than the specs lead you to believe. To get the faster response times, they are optimised for low-contrast transitions. The worst-case scenario for an LCD pixel is having to switch from black to white (or the other way). So when a lot of pixels have to change contrast quickly, LCDs do a really nasty pixel-level flickering that you wouldn't see on another display technology (even old CRTs).
The worst example is a 1:1 black and white checkerboard pattern like this: http://protie.sweb.cz/checkerboard_1920_1080.gif . Be sure to view it at 100% without any scaling - now scroll the image slowly in your browser. LCD screens will flicker like crazy (but some screens are worse than others).
What that means for footage is that any moving high contrast edges, and especially where there is a lot of small contrast detail like grass, tree branches etc, will flicker on an LCD screen - but it's the screen causing it, not the footage. I see this effect quite clearly in the last video @Ian_T posted, in the earlier tree shots (especially around the grass blades), and I've seen it on my own 24p GH2 footage.
That's partly why I'd like a hack that can disable sharpening altogether, -2 isn't fully disabled. It would also give a more smooth cinematic image and allow better post sharpening.
don't know if you have explored this tearing problem on your computer much, but if it is the type of tearing i am familiar with, it could very well be a problem of your video renderer not vsyncing properly or at all. on windows xp there are many video renderers depending on your video card capabilities and drivers, from the standard "video renderer" to "video overlay", VMR7 and VMR9. All have varying ability to vsync properly. On Vista and Win7, EVR renderer generally solves the vsync problem. the best way to find out would be to play with media player classic home cinema which gives you access to many different renderers including evr and evr sync and d3d9 fullscreen with many different vsync options. most importantly it has a "tearing test" to show vsync problems (it draws a red line travelling across the video to see if it doesn't line up properly).
another very useful tool in mpc-hc that everyone here should probably check out before blaming the gh2 is the playback graph which shows you in real-time graph form the timing difference between what the video decoder requests of the frame timing, vs what is actually displayed on screen (jitter). See here for example of detailed statistics: http://imageshack.us/photo/my-images/827/capturestat.jpg/
To my eye, this "strobing" effect is the same effect seen in any theater where a feature film is being exhibited. Features are shot and projected at 24 fps, as we all know. But, as I say, "to my eye".
@bezerk55 There is nothing different about your 3 videos that I don't already see in every other HD video on the Web from any camera. If anything what I see is "tearing"...which I've already mentioned is a sort of pet peeve of mine with ALL HD videos I've come accross (No matter how cheap or expensive the camera). The faster the pan...the easier it tears. This is not GH-2 specific.
With that said...I challenge any of you making these "strobing" claims to post footage like bezerk55's with a camera YOU think doesn't display ....um....strobing.
Oh...@CobyD thanks for your footage. I see no difference in it either.