Correct me if I'm wrong, but isn't this percieved stutter effect caused by clipped highlights? When highlights are clipped they will create a hard edge on overexposed areas, even when there's motion blur in the image.

I would suggest a motion test where the scene is shot underexposed and then boosted in post, where highlights can be handled better.

@itimjim To be fair, only a select bunch of people need GH2 hacks to begin with. What's your point?

Clearly, here we are talking about people who do care about image / motion quality. Excessive motion strobing on GH2 is very real, and this thread shows that actually MANY people noticed and tried various workarounds to circumvent it. (and some people even gave up using GH2 as video camera altogether because of motion issues!)

Current workaround is to use 1/30 or 1/25 shutter in 24H mode. This introduces more blur than the standard 180-degree shutter (1/50) would, and thus masks/smoothens the strobing.

Question is... do hack developers have any technical ability to fix the strobing at 1/50, and if yes, are they trying?

@driftwood @LPowell @Ralph_B

Actually this is a very good question, @MisterJ

Do the esteemed hack developers take into consideration GH2's excessive motion stuttering in 24H mode, and can they do anything at all, technically, to improve (minimize) this unpleasant motion stuttering/strobing at 180deg shutter?

drops into frame doubling mode, 2 frames the same

Two identical frames @ 50fps =25 fps, (shot on twos). I wonder what this does to shutter-blur?. A single, half-blur, seen twice with a stuttering gap in the middle where un-filmed movement takes place? (!) Best avoided, I think.

When the shutter is less than the frame rate in 720 50/60 on the GH1, the frame rate drops to 25 or 30fps

@Rambo -Just to clarify, If you set your GH1 to 1/25th of a second at 50fps, then the camera will default to 25fps?

The other culprit may be not really locking-in the shutter speed (say in Manual mode) , we've also noticed GH2s resetting a shutter speed [e.g. so as to lower exposure]. This can be the reason behind some under-blurred shots.

@Mo7ies Hi Yeah I agree...I think its worse when the bit rate is lower and it definitely appears that all I frames seem to work very well on 24P. I am not 100% sure of this yet, but...so far it seems that way from my own tests.

I found Quantam 100 to be very good in 24P and I also found Crossfire to be very very good (incredible actually)... it seems to be the same approach as Quantam (Intra) but the data rate is higher...bloody nice...but hungry LOL!!

If you try it...let me know what you think...it's always good to compare notes.

On the other hand I found Cluster4 (G) to render very nice detail in 29.97...I was amazed at this cause its a pretty long GOP setting and a low bitrate too, yet its detail seems really good. I havent tested it outside tho...yet, but so far so good. The 29.97 patch that is in Crossfire (the original one) is not nearly as good as Cluster4 (G) IMHO.

I think Driftwood was going to combine the Crossfire 24P and the Cluster4 (G) in one Patch, that would be great (best of both worlds). Of course we may not wish to shoot in 29.97, but its would be nice to have an efficient and clean looking patch that is a low bitrate for 29.97 and a stellar 24p frame rate setting...all on the same patch.

Yeah...About Ghost Rider I did watch it in 2D...so I dont know what caused that strobing, I saw it in the fight scenes as well...even in the restaurant, it did look a lot like like the type of strobing/shuddering the GH2 gets, but not as pronounced and therefore a bit more bearable.

Cheers

@driftwood Thanks very much...and also thanks @Roberto for your tests. I did a lot of tests a while back using 25P...cause thats the setting I need the most in Australia (HBR) TV out PAL. But at 50 shutter that strobed too, so I dont think absolutely even shutter divisions will be the answer, although if uneven shutter is crushing bitrates at 24P, that may be causing other problems. Mo7ies is right that 1/30 shutter lessens the effect, but I have noticed that in hi contrast areas even the slower shutters cause this stuttering/strobe effect at 24P As an aside I was watching Ghost Rider Spirit of Vengeance on Blu Ray the other day, I think it was shot on a Red One Mysterium X, anyway a lot of the film looks really good. There is quite a bit of strobing tho...as their are a lot of shots where the camera moves a lot, and there is a scene at 1hour-6mins-04 seconds where they run the camera forward at medium pace over some white rocks and the strobing of the rocks is very noticeable. However it was still quite a bit less strobe than the GH2 delivers, and although annoying ...it was sort of acceptable. Personally I think we will go a long way to finding a cure for this when Panansonic has their global shutter thing perfected, obviously they are aware of these issues for them to be trying to develop a new type of shutter system. Anyways in the meantime I have found Driftwoods all Intra settings (Crossfire and Quantam 100) to help in the 24P settings along with the slower shutter rate. And of course in 29.97...the problem largely goes away.

@mo7ies

Sorry, @mo7ies, it was @Astro who wanted to see the slow pans.

I am pleased to note that nobody is muddying the waters - there are several ways to examine stutter; you and I agree there's something going on with blur.

Others are looking at other phenomena. I agree also that stutter itself is such a big issue that it may well deserve different threads. It certainly needs to be examined by one possible contributing factor at a time, preferably by one person/team at a time.

Now, back to my work on motion blur:

At the other side of the barrel with the multiple dots was a 2" pink line. same speed, same camera as before. Once again I've made up an animated GIF.

@mo7ies

Yes, I know you are impatient to see results for moving vertical lines. First I had to set up something to see if blurring was happening correctly at all. That part is done.

I had already tested fast-moving vertical lines (see my jello test). The blur was correct for fast shutter-speeds. I can try it again at a lower shutter speed for you.

Next, as you say, I will set up a slow-moving background of contrasting vertical lines, to look like the moving forest which is so often seen stuttering.

I never said "slow-moving backgrounds" were a problem.

The problem, in my observations, arises when there are any vertical lines moving in the frame.

@driftwood

1. Thanks for testing this aspect of shutter speeds.[Can we call it synchronisation?] As I imagine it, an electronic shutter 1/25^{th<s/up> of an arbitrary 50 frames per second would open for 1/25th of a second. The rest of the frame would be 1/25th of a second of darkness, before the next frame would repeat the process.}
2. I was willing to bet that my own motion-blur tests would show insufficient blur at certain shutter settings - even with fast-moving backgrounds. Well I've tested backgrounds and found this isn't the case.
3. I still have to set up some repeatable shutter-blur tests using slow-moving backgrounds (which @Astro and @Mo7ies cite as their most likely stutter-producing scenario).
4. Finally, somebody needs to look right into @nomad 's idea of attack/decay of how these electronic shutters actually work. -

During my weekend of tests on 720p modes please remember if you enter a non matched shutter speed against a fps setting (e.g. 1/50 shutter on a 720p60 recording) you are more than likely to suffer problems and perhaps this could be a cause of enhanced strobing. This imbalance also creates smaller bitrate file sizes.

Ensure your shutter speed matches the frame rate (check) and in divisibles of it.

Here's a quick check using the same subject matter with 720p60 at 60 shutter (pic1) and then 50 shutter (pic2). Notice the odd B frames - all recording on the same test setting.

This may be a red herring but I'm further testing a number of users settings & other modes such as HBR.

Another test I will be looking into is timing. Perhaps we need to address the time_scale and ensure 24p/25p and 50i is set to 50000 and not 48000, and 30p and 60i is met with 60000 or divisibles of above. Again it could lead to nowhere. As soon as I get a spare moment from an edit Im working on I will conduct even deeper tests.