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25p official topic, aka Don't cry for me Argentina
  • 236 Replies sorted by
  • rozrozrozroz
    could someone (Vitaliy?..) please explain (i'm not an expert)
    what's the difference between the AF100 25P capability VS the GH2 failing to have this mode?
    is there a GOOD reason for Panny not being able to put 25P on the GH2?
    maybe hardware decisions in order to perform a native 24p?

    thanks
  • alcomposeralcomposer
    Hey @rozroz...

    Basically there is no way to 'understand' this... Panny can do anything that they want.
    There is no reason why the HDMI output is 8bit..?

    The simple answer is that the AF100 is Panny's flagship 4/3 film camera... and they made it so.

    The good reason why there is no 25p in the GH2 is that they didn't even think that the GH2 would be used for what its 'going' to be used for. For them- its like watching a car crash in slow motion.

    What did @VK say? Something like Panny being a bad mother that is now in a Hotel room making another baby? There was also a photo...
  • rozrozrozroz
    well i guess they really don't give a s**t..
    but still- maybe there IS a logical reason for, let's say,
    not being able to put a native 25P where there's a native 24P? (just on GH2, not AF100 with different hardware)..
    or am i talking nonsense?
  • MihuelMihuel
    @rozroz
    There is logical reason - money.If you do not know what is going on, it's always about the money
  • rozrozrozroz
    but if so, then it's still some kind of a software issue ?
    or they basically built the GH2 hardware specifically this way in the first place ?

  • Mark_the_HarpMark_the_Harp
    My GH2 box has PAL on it. So I do feel like I've been "done"! However, it's still a great camera.
  • chefchef
    So I'm about to get me a GH2, I'm in a PAL land 25p: in anycase there will be the patch to make it 24p cause my footy gonna go primarlily on the web so doesn't make any difference..not?
  • _gl_gl
    Chef you have it backwards - the GH2 has 24p but doesn't have 25p (yet ; ). For the web it doesn't matter (you also have a 30p option if you use MJPEG).
  • sam_sticklandsam_stickland
    @madact I understand the 100Hz frequency issue in the 50Hz AC lights, requiring either a framerate "in-sync" with it (e.g. 25p), or a shutter speed that's a multiple of 1/100 (e.g. 1/50).

    In NTSC land with a 60Hz AC supply then 30p/60i doesn't have this problem either.

    But 24p isn't in-sync with a 60Hz AC signal either (120Hz flicker), so this problem will also exist in US unless a shutter speed is used that's a multiple of 1/120? e.g. 1/120, 1/60, 1/30, 1/24, 1/20 etc. None of these are particularly close to a 180 degree shutter.

    So this light flicking issue is a _global_ issue with 24p, which can only be mitigated by carefully choosing the shutter speed.
  • madactmadact
    @sam_stickland - sure, not complaining about 24p isn't in sync, that's not the issue. We're not talking about 24p, we just happen to have a heap of half-baked assertions that "24p and 25p are really quite similar, so why not just use 24p and fudge it a little"?

    The problem facing people is that you can shoot 1080p ntsc video at 30fps, which is just fine for American mains sync and American or Jap TV, but you can't shoot 1080p pal AT ALL (which some here would really like to).

    What irks me most about it is how Panny proudly trumpets on their website that the sensor captures 1080 at 50p (PAL) or 60p (NTSC), a spec which, as far as I can tell has NO EFFECT WHATSOEVER on what the camera can do - it's like saying "my car can do 500bhp, when the turbo is linked by a shaft to a fighter jet engine" ... totally pointless assertion, even if true. [ http://panasonic.net/avc/lumix/systemcamera/gms/gh2/movie.html - "Now the DMC-GH2 can record high-resolution full-HD 1,920 x 1,080 movies in astonishing smooth 60i (NTSC) / 50i (PAL), doubling the sensor output from 24p / 25p to 60p / 50p" ] Good job there, Panny.

    The one interesting thing from *that* is that it implies that the sensor could *perhaps* be read at 50p and frame-dropped (esp. as shutter can be set slower than framerate... every second frame of 50p with 1/25th shutter would look a lot like 25p to my eye, I think), but apparently that's not an option? Maybe Vitaly can confirm... it could be that the sensor 'captures' 50p (i.e. the CCD pixels are always on the chip :-/ ) but can't output 50p to the next thing in the chain...

    On a side note - for those who are shooting for broadcast, will the customers not take 1080/50i?
  • mpgxsvcdmpgxsvcd
    @Vitaliy

    So close yet so far. Thanks for all of your great work. What aspects should we concentrate on first with the new Ptool. For example do you think there is the most room for improvement in 720p or do you think it will be possible to get 25p to work properly?
  • mpgxsvcdmpgxsvcd
    You can easily get 25p with a stock GH2. Just shoot 1080i and deinterlace it. So many people complain that 720p doesn’t have nearly as much resolution as 1080i. You can also get 1080p @ 25 FPS from the GH2 by dropping the shutter speed below 1/50th.

    Now in reality the 1080i mode has terrible vertical resolution so this isn’t really a viable solution. Shooting 720p @ 50 FPS with the upcoming hack will produce perfectly acceptable 720p @ 25 FPS. You can always upscale it to 1080p @ 25 FPS if it must be 1080p.

    I wish I had a GH1 to test against the GH2’s 720p mode. The GH2 ‘s 720p is so much better than the non GH series cameras.
    GH200001 AVC 720p 0 IR.png
    1280 x 720 - 1M
    GH200001 AVC 1080p 0 IR.png
    1920 x 1080 - 2M
    GH200002 AVC 1080i 0 IR Yadif Deinterlace.png
    1920 x 1080 - 3M
  • MimirsanMimirsan
    GH2s hacked 720p 50p mode is very good indeedy...almost 1080p looking in terms of other camera comparisons.
  • stolpis100stolpis100
    Right that's it, i'm getting one. The only ones I've seen physically available in shops have the 14-42mm lens. Am i right in thinking the 14-140mm is the basic starting point lens I should go for? This is my first real step into camera work, I've always hired DOPs for previous projects.
  • madactmadact
    All of which is still 1080p in the same way as that iPhone 3 app that 'upgraded' the 2MP camera to a '7MP camera'... man that was hilarious. No argument that the camera is awesome, I agree that good 720p is better than crappy 1080p, and I personally will be fine for my needs with the modes available (now that we can get 24, 30, 50 and 60 together). But 1080p PAL would be even awesomer :o)

    @stolpis: lots of threads in the gear section... I'm going for a 14-45 for starters myself and maybe a fast prime like the panny-lieca f1.4 or the nocton down the track, but I have some old Pentax K-mount glass and a Volna-3 on a tilter, that I plan to re-use. Gotta love micro 4/3, it'll take (almost) anything.
  • mpgxsvcdmpgxsvcd
    @stolpis100

    I would say the 14-140mm is a great starting point with the GH2. Its small aperture is not useful for the GH1. However, the GH2 has a 1-stop advantage over the other m4/3s cameras so the 14-140mm is usable.

    After that I would get the upcoming 25mm F1.4 over the 20mm for video. If you manually focus or use AFS the 20mm is fine for video. However, the 25mm looks like it will be an ideal video lens.

    After those I would say the 45mm F1.8 or perhaps the 45mm F2.8 with IS would be good choices. However, I really like my old MF lenses in that focal range.
  • fatpigfatpig
    to me it looks like it could be possible to use 50p sensor mode and encode it to 25p 1080... time will tell if VK can do this :)
  • ElenionElenion
    Well, even better if we could record at 1080p50...
  • Mark_the_HarpMark_the_Harp
    @mpgxsvcd "You can also get 1080p @ 25 FPS from the GH2 by dropping the shutter speed below 1/50th."

    Could you just explain that? I think I get what you mean but I'm not sure! And of course it's not going to have the data rate of the stock 24p mode unless you also tweak the data rate settings on a hacked camera.
  • Donnie88Donnie88
    Any further testing of 1080/25p to see if there is hope?

    Also there seems to be 720/25p, has this been tested at all?
  • ElenionElenion
    @Mark_the_harp
    I think mpgxsvcd was referring to the fact that if the shutter goes below the fps the camera record just the frame it needs. This means that if you record 50p at 1/25 the camera record just 25fps (that you have to interpret during editing), but the fact is that gh2 doesn't have (yet) 1080p50, it has only interlaced ones, then you can get 1080i25.
    I don't think that it could be a good solution.
  • Donnie88Donnie88
    It wouldn't be a good solution. As Elenion said, the 1080/50i is interlaced (it's not 1080p/50) - so you will get half vertical resolution is every other frame is dropped. Big no-no, that option is out of question.

    It does seem 720/25p might be possible, but not sure.
  • ElenionElenion
    If you want 720/25p just use 720p50 and then frame skipping
  • Donnie88Donnie88
    And 720/25p exported as 1080/25p shouldn't be too different from native 1080/25p, right?

    If so, this does seem like a temporary solution.

    How would I skip frames? Surely not manually?
  • ElenionElenion
    It depends of the software, in premiere you have to select "interpret footage" and the project has to be in 25p. It makes all by himself.
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