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Flicker effect on my gh2 running flomotion?
  • Anyone have a diagnosis for this flicker effect on my gh2 running flomotion? A possible solution? Heres a vimeo link to some of the footage.

    __http_://vimeo.com/46113751

  • 19 Replies sorted by
  • How about to think about fluos that cause this, not GH2 or hack?

  • While the dismal lighting was obviously problematic, more details on your shooting conditions would be helpful.

  • Well, yeah the lights were available light fluos which I know can cause flicker, but I've shot with the same set up around fluorescence before and not had the problem. Don't get me wrong about this I love the hck and have great success just wondered what could be the cause of this. Also, the viewfinder would on occasion cut off for a brief moment while shooting. Any thoughts. Thanks so much for the replies.

  • Well, yeah the lights were available light fluos which I know can cause flicker, but I've shot with the same set up around fluorescence before and not had the problem

    One faulty ballast or one faulty lamp is enough.

  • Gotcha. Thought so. Thanks!! By there way, you guys do wonderful work here. It truly is amazing.

  • CTK121275 >Also, the viewfinder would on occasion cut off for a brief moment while shooting.

    Check the EVF proximity eye sensor is not enabled.

  • I had a flicker issue once on a scene i did a few weeks back. The flicker came out of nowhere. I was confused. The gh2 was hacked. Don't know if that was the problem or not. But all I did was turn the camera off for like 2 minutes and turned it back on. No more flicker. Weird. That only happened once though.

  • I get the same issue all the time under every lights...

  • That's the flicker I mentioned in another thread, i believe. I've seen strange flickering, especially in neutral color walls and things when the frame is underexposed even in tungsten lighting. When moved frame by frame I would see some frames would have either a strange tint in the noise or the noise would form some kind of block pattern but isn't the same as macroblocking at all.

  • I'm experiencing this strange flicker as well. I've made sure myself I selected the right shutter speed (1/50). I'm in PAL land, and I can notice this strange waving-darkness that comes from the bottom of the frame. If I overexpose a little, this strange flicker is not that obvious, but it's still there. It also happens with no fluo lightning. I'll try to provide some footage, so someone could tell me what's going on...

    Congrats for the great job you all do around here! ;)

  • here it is:

    password: weirdflicker

    May be you won't notice it unless you turn on HD or download it.

  • I live in PAL land and I had much the same issue recently when I did some tests at night in an exterior area lit by very harsh, industrial lights -- not sure exactly what they were, but not typical flourescents. I forgot to check the GH2's settings, so I was inadvertently shooting in "Cinema" mode (24fps). When I switched to "HBR" (25fps) all was fine. It's a long-standing problem left over from film days: a mismatch between an electrical light source (typically 50Hz in Europe) and a shooting/capture rate of 24fps. The well-documentated inferiority of the GH2's image quality in "HBR" mode when compared to "Cinema" is one of the biggest drawbacks on this camera, IMHO.

  • @sherwood So there's nothing we can do but to use HBR (25p) in order to completely avoid it? :( Really sad to hear that.. I was about to return my camera.. I thought it was broken or something, 'cause I never saw something like this on a 7D shooting at 24fps...

    There's another flickering-related mystery with my GH2. People complain all the time about the flickering they get when they shoot at 50p/60p and their shutter speed is not in sync with the frame rate (and the lightsource is a fluo). Well.. call me weirdo but I like the strobe flicker that appears when pulled down to 25p -in my case-. The point is that I'm unable to obtain it...no matter what I try. Before pressing the rec button I can see it.. but once it's recording.. the flicker disappears... it's like if the camera compensates the difference between frame rate and shutter speed..somehow. It randomly appears though, but just for a few seconds.. and only if I point the camera towards the lightsource. What am I doing wrong? Is this fact also related to PAL users?

    Any other voice that can contribute with these mysteries? Any comment will be appreciated.

    Sorry Vitaly if this isn't the right place to post this.. I've been here for a long time but never dared to post a thing. And sorry you all for my english, I'm Spanish.

  • You shot 23.976fps under 50Hz lighting, the only workable shutter speed that minimizes "rolling" flicker (to the point where is no longer an issue) is 1/50; this is quite apparent in your own footage. There is flicker at 1/40 but not so at 1/50. If you shoot 25fps under 50Hz lighting you can use any shutter speed.

  • @laaldeapro "So there's nothing we can do but to use HBR (25p) in order to completely avoid it?"

    Welcome to the crazy world of international TV/video and film standards! This is a thorny and complex issue that you'll just have to work around because the electrical system in Europe is not about to change soon. The effects from different light sources vary, so you'll need to experiment. In general, I have found that incandescent lamps (including quartz halogens) are much less of a problem than flourescents and high output industrial lighting. I'm not sure about LEDs -- perhaps someone else can share their experience. In Europe we've traditionally just shot at 25fps (the TV and video standard) and made a -4% adjustment for 24fps cinema projection. But as was already pointed out, the implementation of 25fps in the GH2 ("HBR" mode) is not as good as the 24fps (23.976 if you want to be precise) "Cinema" mode.

  • @radikalfilm @sherwood, thank you both ;) It's strange though, on my room (incandescent lamps) the flickr is almost invisible. On the bathroom though, it's there.. everywhere (incandescent lamps too). Maybe my home's electrical installation is the problem..

    @sherwood.. could you tell me something about the non-flicker at 50/60fps (no matter what shutter speed used) pulled down to 25/24fps? They are not the common long tubes if this may help.

  • @laaldeapro Flickerless using FSH 1080i modes. But stick to 50 ss for 24p.

  • Flickering won't occur also in 24p if you just mind the mains frequency of the country where you are shooting your video. So if you want to shoot in the USA using 24p under fluorescent light without flickering, use 1/30s 1/60s 1/120s etc as they are dividable with 60Hz of the mains / power line frequency.

    In Europe, use 24p with 1/25s 1/50s 1/100 etc to avoid, or 1/40s, 1/30s etc to get the flickering - like I for example intended to in this video by 6m:20" to get candle-effect (it made good combination with stable tungsten light), and changed to 1/50s by 8:40 to avoid flickering: http://www.personal-view.com/talks/discussion/5673/amazing-traditional-event-caught-by-balazers-cake-v2.3#Item_1 all shot in 24p.

  • @tetakpatak: the theory doesn't quite hold in my testing. In 50Hz countries @ 23.976, really the only SS where you DON'T get flicker is 1/50. Just set it and forget you have the control; work around exposure issues with more/less light and aperture.