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GH2 in 24p: noticeable "strobe effect" with any motion in frame?
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  • I also would be very interested to hear the difference in strobing amount between the Wide and Tele ends on the standard 14-42mm lens, in your opinion.

  • @Astro : and to complete mo7ies' question, were you able to compare panning quality of 14-42 lens with that of 14-140 lens ? (or 25mm panny, or olympus 12mm, 45mm)... i know, asking a bit too much, but seems i'm thinking about ordering these lenses soon, i'd like to know if i should also have a 14-42 for panning scenes only

  • Thanks for the tests and for your detailed post. Did you test any manual lenses, like Nikon/Canon with adapters?

  • @mo7ies

    Hi.. I have done a lot more tests on this issue, incl using hacks like Sedna (I frames) and Cluster (Mixture IPB Frames) etc... bottom line is there is not much difference when you use different hacks, which is to be expected. Tho I suspect that the more I frames there are, the worse the strobe will be, because of the efficiency of the codec. it seems that a mixture (IP and B) lessens the effect somewhat.

    Its true that using a shutter speed of 30 on 24P does lessen the effect of strobbing when panning...not completely, but it is an improvement. 29.97 is still the best when it comes to panning the camera without strobe affects, although if you pan quite fast any setting will do it. However 29.97 or 25P (HBR) has its problems (as pointed out earlier) plus it renders less details than 24P when the camera is still on a complex scene. I did extensive tests on this...all types nature, guitar pans, close ups etc..

    Also testing with the old Kit lens 14-42 vs the 20mm F1.7...surprisingly the 14-42 is MUCH BETTER for moving or panning the camera (I tested the 14-42 with the cameras internal stabilizer/shake on and also off) With the stabilizer enabled or disabled its simply much better than the 20mm lens (although I love that lens)

    The 20mm is much harder to control and somehow moves very stiffly in 24P especially (compared to the 14-42) Now I know the 14-42 gets a bad rap, but personally if I shoot in 24P and want to pan then I will be using the 14-42, of course the 20mm is probably better for stills and obviously low light as well (DOF)

    I also tested footage in Adobes CS6 warp stabilizer in Post...nice results (like a glide cam) but it does soften the detail a little, so I am not sure about that.

    Well thats it for now.

    Cheers

  • Yea something like that, it was like mega-strobing :D I was too frustrated at my mistake to take time and analyse the default :s (i'm trying to master all the technical stuff in order for me to use this cam soon on fiction shooting, where it's absolutely important to avoid such mistakes or else it can ruin the work of a whole team). I tried an average-speed pan earlier in my room, with the cam on an office chair, i'm still not very very pleased with the fluidity, but strobing seemed to be less (it was also a low-contrast image, with very little detail, bit rate remained around 15 Mb/s)

  • At 1/20 shutter, you are forcing it to be open longer than the duration of each frame which is still set at 1/24 of a second. So you get a stop-motion effect. This is very different from strobing, though.

  • Just got back from a car drive with my GH2, had some trouble with the light (sunny day, lots of trees, and random clouds) and a very dirty windshield (oops), other than that, movement is great... really need to focus on details to see some strobing, but this could be just normal "cinema" style. (i'm talking about clips i viewed MTS, on windows movie player, 24p mostly, also tried 25p, but doesn't change anything). Hack pushed writing speed to 68 Mb/s , everything works fine on my sandisk class 10.

    At the end, i wanted to take a static shot of many cars passing by, cars in shadow against a sunny background, but i had inadvertently touched the shutter speed (while rapidly trying to change aperture), put it at 1/20, and strobing was awful :s I hope i can try it again with 1/25 soon.

  • Yea, possibly driftwood, or flow motion or sanity v4, one of these it must be.... (it wasn't my intent to hack my new gh2, i wanted to get the best out of normal settings first, but panicked with that strobing issue and thought that "flow motion" or "aquamotion" meant that the movements would be more fluid :D

    well, i don't regret the patches anyway, and i've been learning a lot lately.... still need to find a way to be sure that i can get no excessive strobing after editing (like when putting it on a dvd or so)

  • Well, pantyhose/filters will reduce overall resolution, while slower shutter speed only affects moving objects. IMHO, the latter is clearly preferable, because moving objects already are blurred by motion and thus lack resolution.

    BTW, stock lenses like 14-42mm are also very sharp.

    In any case, my current experience is to shoot at 1/30 or 1/25 shutter, and the strobing goes away.

  • @mo7ies - thanks for these posts. Coming from half a lifew of using film, I'm amazed at how much you can slow the shutter speed down and maintain excellent results. I have the Pana 25 1.4 and yes, it's sharp as a rat turd, and with that comes the strobing and the frizzle shite that pulses over contrasty zones. o reduce stutter, I've been trying out the vari setting with 80% then playing it back at 24 with a 25% speed up in Avid. It works okay, havent' tried synch sound though. (there's no sound in vari mode.; I'll bet that new 12-35 is going to give us that really sharp "problem too" Might have to try shooting through panty hose, If I can nab some.

  • Was it one of the Driftwood patches, maybe?

  • With 1/25 shutter, i get acceptable movements in travelling, if i don't go too fast and avoid very contrasted stuff... now i'm waiting for my new video tripod for more serious testing. I'll have to find dollys, cranes and so on (a guy i know has a self-made crane, 4m high).

    And today i benefited from a brief heavy rain episode to push the camera. Resolution is awesome, i can clearly see the rain drop traces against a dark wall that is like 50m away from me. The patch that i still don't remember went to 51 Mb/s for that. Looks awesome. (and will look better when i use a tripod).

  • Yes, kit lenses are amazing for sharpness, and they do have somewhat helpful IS, but not fast enough at all. Also I noticed some crazy flaring on 14-42mm in wide settings. Looks like a romb-like bright spot, very ugly. I saw it on two different copies of 14-42mm, with two different GH2 bodies, very repeatable. Not cool.

    If I may recommend this Panny pancake lens: http://goo.gl/6IHWb 20mm f1.7, it is reasonably wide and fast enough and it really produces awesome looking video.

  • @mo7ies : thanks for your quick answer, but i get the same excessive strobing at any shutter speed (ok, slightly reduced at 1/25, but still enough to become epileptic). It becomes fluid with Motion2 on the Splash pro ex, but some flickering appears on the most contrasty zones (panning with the black frame of my computer screen against a very light yellowish wall). (ps : i pan with and without stabilizer, with arms, waist, or on a spinning office chair, but none of these affects the strobing). thanks for the tip about the sanity patch and the card. I'm waiting for better lenses too (ordered panasonic 25mm, for now i have only the kit 14-140 which reaches its limits very rapidly when shooting indoors).

  • So far I think the best overall patch is Sanity v5 by Ralph_B. Card: as usual, I recommend this one: http://goo.gl/gbQf4 - it it very fast, reliable, and spans indefinitely in 1080p24H and 720p60 modes. Strobing: to avoid it with GH2, shoot at 1/30 or even 1/25 shutter. If yo ualready shot with 180deg shutter (1/50), then your strong strobing is baked-in, and can be treated in post with the forced motion blur effect (see my post above with before/after examples and After Effects workflow). However this is too much of a hassle for something that is perfectly achievable in-camera in real time, so again - do shoot at slow shutter speeds of 1/30 or 1/25 on GH2, and motion will look OK.

  • Hello, i'm new here. Bought my GH2 last week after doing countless research on the quality, and of course, i never read anything on the strobing issue before noticing it on the cam :s At first i thought i was a moron for setting a too high shutter speed, but then i verified and it was 1/50 for 24p. So i installed firmware 1.1, and the 25p gave the same strobing. So i tried various patches here (thanks for the great work btw), but still same issue.... I read up there that Splash Pro Ex solves the issue in Motion2, and i just tried it....it does work. (it's not as fluid as 50i, but then of course the point of 24p is to be less fluid-ish i guess).

    So, could someone now give advice on the workflow ? - My objective is to produce both documentaries are fiction films (to be sent to festivals, via DVD, and shown on internet, maybe sold to TV).

    Which editing program (windows compatible) do you suggest ? Should Splash PRO EX be applied before editing or after ? (sorry if this could offend the more experienced here, i have very limited knowledge of workflow) For PAL people, is 24p or 25p the most compatible mode (for dvd export and internet) ?

    And any recommendation on the patches ? (noobish as i am, i tried 4 different ones, and forgot which one is on my cam :D ), for now i use SanDisk extreme class 10 30MB/s, which patch works best on it ?

    Thanks in advance :)

  • @feha and @mo7ies Yep good points. Basically as my stuff is mainly music videos and I dont really need the long recordings, so spanning is not really an issue and I wont need a 24p timeline, I can do it in Premiere or Vegas and keep it at 30p from beginning to end.

    Its just nice to know tho...that 30P does not have the strobing/flicker issues like 24/25P does ...and if I need 24 or 25P I will just make sure I dont move the camera too much. But yeah...all good points, at the end of the day I guess it boils down to the fact that you have to plan your workflow in advance from beginning to end before you start shooting. Cheers

  • @Astro problem is, 30p does not translate into the correct cadence if inserted into 24p timeline in post... Also, 30p usually does not span on the card, yet 24p does, allowing very long recordings - especially with @Ralph_B 's Sanity v5.

  • @Astro , thats great but the probematic if client wants 25p PAL ... I tested HBR 30p and works great as you said.

  • @feha Hi...yes I converted back to 25p on a video conversion editor and also in Vegas Pro 11.0. Both looked significantly choppier (anyone could spot it, no trained eye needed), mind you there was not the flicker that 24P gives as well (regardless of the many hacks and settings I have tried).

    Today I did an indoors pan across a metallic blue Strat (I did many outdoor nature tests too) Anyway although the GH2 was handheld and not panned that smoothly on the Strat pan, the quality and general smoothness of that video filmed in 29.97 was $%### GREAT!! I was over the moon!! No Strobing!! No Flicker!! filmed at 29.97 1080P (HBR) in NTSC with the Panasonic 20mm F1.7 lens, ISO 400, Ap 4.0 and the shutter can be at 60 for 180% shutter or 50 for lights in PAL land. The result was great!! So for me anyway I will stay at 29.97 all the time from now on.

    I did try the 720P 50/60P settings much earlier with various hacks where they were upsized to 1080p they were good too, but personally I could see they were ultimately enlarged to 1080P and (to my eye anyway) they seemed to lack the resolution that the 1080P 29.97frame rate gives. I guess the bottom line is that the 29.97 is the fastest universal frame rate that the GH2 does at 1080P, and it works...who would have thought an extra 5 or 6 frames could make such a difference, but they do. The added bonus is Youtube, Vimeo, BluRay etc... appear to accept the 29.97 rates, so I will stay there all the way from now on. I also just read that LPowell shoots mainly in that rate as well, he described it as less problematic LOL!! Very true!! Cheers

  • @Astro , great tips. have you tried to convert back in to 25p PAL on NLE ? Does it work ? I tested shooting 720 50p, this works great even with up scaling to 1080 ... (keeping 50p else is not that smooth)

  • I became obsessed with the strobe issues on the GH2 (especially when panning) accompanied by an annoying flicker. I live in PAL land so I used the HBR 25frame and also the 24P, and tried a lot of the hacks, nothing worked, filters, Screen resolution refresh rate, turning off I.R, all manner of shutter speeds etc..decreasing sharpening, tried all types of conversions and viewing as well ...Plus I read countless forums on everything from 120hz screen refresh rates (not many people have those anyway) to what type of media player to view thru (most people dont have those either)...so your clip will still judder when others view it .

    However my trusty old TM700 at 1080/50P does not do this at all, but if the footage is converted to 25P then it is not as smooth, so frame rate definitely helps a lot regardless of the arguments against frame rates.

    Then a little while back I read here the suggestion to shoot at 29.97 all the time

    http://www.hdvideopro.com/technique/miscellaneous-technique/help-desk-did-i-judder.html

    So I switched my cam to NTSC, set the shutter to 50 (for lights in PAL land) and 60 as well...and lo and behold the problem was 99% FIXED. No more obvious flickering (day or night), and very little strobe effects AWESOME!! Try it ....do some A/B's you will see a big difference, and the best part is I can use 29.97 for just about everything, even tho I live in PAL land, so for me anyway the problem is solved...no more 24P or 25P.

    IMHO Cinematic look (24P) simply does not work that well on current digital CMOS cameras unless its absolutely still or very close, its not a Cinema look, its more of an epileptic fit inducing look if you do any panning...29.97 has made my life with the GH2 a lot less problematic!

    Cheers

  • On GX1, you can set the shutter speed (angle) to 1/50, 1/60, 1/100, and 1/120. One can easily eliminate the strobe effect by using the appropriate shutter speed. So I think there is nothing to do with the frame rate.

    By the way, does anyone know what is the benefit for shutter angles larger than 360 degree? I just noticed that in SH manual movie mode (720p/60/50), it is possible to use 1/30s or 1/25s, which is about 720 degree.

  • I've never seen a frame of film with evidence of a shutter once the camera is rolling (and they shout "Action!"),

    What I do see in the posted shots of stuttering GH2 are frames where the stated exposure time is greater than the actual exposure. When I get back from this bush trip I will try to reproduce the error and then post some still shots.

  • Very true, Nomad. THe mech. shutter is out of focus. I'll try to wok within the confines of the digital system, including lowing the shutter for ccertain shots. And if I use a rental again soon, I will try the Tessive filter. It really seems that sensor and resolution might take a back seat to motion imaging as is discussed here. I guess 48fps exhibition is one answer. But a long time coming (for the digital age) Thanks