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Frame Rate Choice for mixing GH2+GF2
  • rubberbanditorubberbandito

    I shoot documentaries: I use GH2 for primary camera (1080 24p all the time) and want to use my GF2 as a B cam (using 1080) and stunt cam (using 720 for high speed). I am in NTSC country. I will be using the hack on both. I use Premiere Pro and like most my stuff goes on vimeo.com but I hope/plan to sell some stuff on Blu Ray and digital download.

    If you have a GH2 (A cam) and GF2 (B cam) what frame rate do you plan to use?

    Here are the options I have thought of:

    1. Shoot both at 1080 29.97. Pros: A) DVD and Blu Ray encode at 29.97, B) Smoother pans. Cons: A) Hard to transfer to 24p for film and some film festivals. B) No footage you can use for nice slow motion YOUR OPINION?

    2. Shoot GH2 at 1080 24p and GF2 at 720 60p (59.94). Pros: A) Nice 24p filmic motion from GH2. B) Drop GF2 720 60p footage into 24p timeline and it looks ok and you have slow motion possibility Cons: A) the 720 60p to 24p can sometimes look jerky/stuttery. B) Can't use the GF2 1080 res. YOUR OPINION?

    3. Shoot GH2 at 1080 24p and GF2 at PAL 25/50 Does this work. YOUR OPINION? Potential Pros: Ability to use 1080 and 720 on GF2 and still match with GH2. What I have found so far is the PAL footage can look strange with certain lights on in NTSC countries. It sounds like a good plan because you only skip one frame in 1080 footage and only two frames if you use the 50p footage. YES/NO?

    4. Final question, how do you plan to match footage color with GF2 and GH2, using same settings like -1,-1,-1,-1? using Flicker Red on GF2 setting to stabilize shutter at same speed set for GH2. (If you enable CINE style on GF2 you cannot use Flicker Red to set shutter). Possibly in post a simple S Gamma Curve with get GF2 to match GH2 Cine style.

    MY OPINION: shoot 29.97 all the time. Very small percentage of indie filmmakers are actually making movies that go to theaters because its so competitive. Most films play in most film festivals that allow Blu Ray now (except for the big festivals but they allow you to transfer to Beta cam and other formats that allow for 29.97 or 59.94). And most films will go straight to DVD or Blu Ray and never be shown in 24p cinema. And if you get into TV or cable much better to have 29.97 which can also easily be put on a 59.94 timeline if need be (Premiere simply doubles the frames). And in my opinion vimeo.com handles 29.97 very well. So I am most likely going to shoot in 29.97 on both cams and, when needed, use GF2 as stunt cam at 720 60p which will easily convert to slow motion.

    The only thing I do not fully understand is why 29.97 is said to be interlaced. When I drop both footages into Premiere Pro (I do not use Mac FCP or Pro Res bla bla) it renders out as progressive without any problems but am I missing something? Do I need to use Clip Wrap or something on all footage first before editing? In my opinion no but wanted to hear from everyone.

  • 19 Replies sorted by
  • kavadnikavadni

    I am in PAL land here things are easy to choose 25P HBR on GH2 and the 25P PsF wrapped as 50i from the GF2. I would agree with you 29.97 and if you need to go to 24, deal with it

  • stoneystoney

    GF2 don't have 60p.

  • KeithLommelKeithLommel

    Stonebat is correct. 720/60p on the GF2 is really just 720/30p with each frame repeated twice. Before I hacked my cameras, and before the GH2 got a real 30p mode (and before I figured out the 80% speed trick), my solution was to shoot the GF2 at 1080/30p and the GH2 at 720/60p, and editing them on a 720/30p timeline. That gave me the option of just downresing the GF2 to 720p or zooming and panning around as the scene required, and I could get slow motion from the GH2 footage when desired. Now, I'd probably just shoot 1080/30p on the GF2 and use the 80% variable speed mode on GH2 to get 1080/30p on that too, except if I really needed an audio track to aid with syncing, in which case I'd use HBR 30p mode. But the quality on 24p modes (sped up 80% to 30p) seems to be much better than the HBR 30p modes.

  • rubberbanditorubberbandito

    the gf2 is a confusing camera really, but this makes sense as to why the 60p-24p looked jerky to me. now i begin to question why i bought it if i can't use as a stunt cam (mounted on cars, planes, etc--I like gf2 image much better than GoPro). oh well, nothing else out there can you buy for $200 that fits all your m4/3 lenses and has a great image now with the hack. i guess i gotta live with no decent slow motion until GH3 that hopefully gives 48p which I think would be ideal as a standard but probably will never come to be.

    why on earth would anyone ever shoot 720 60p if it is really 30p. it totally makes no sense at all to have that on a camera that already has 30p in higher res, 1080.

    so the gh2 24p sped up 80% to match 29.97 is better than HBR in your opinion keithl? but does not sync properly with external audio? good to know.

  • Vitaliy_KiselevVitaliy_Kiselev

    It looks like 720p60 because of AVCHD standard framerates, I think :-)

  • stoneystoney

    @videohq

    +1. So true. Thank you.

  • rubberbanditorubberbandito

    yes, totally agree, however, story will look like crap if you mix different frame rates. i spent the last 2 1/2 years of my life focusing on content/story making my first film on gh1 http://www.menoflamancha.org/ (mixing with hv30 as well), but needed the help of others to straighten out the mess of various framerates i had (which this forum's LPowell helped tremendously with), which included hours and hours of transcoding on 8 core computers.

    i shot mostly with 60p because gh1 had crippled 1080 codec but thankfully it worked out, after shooting some 80 hours of footage i could use slo mo when needed and have a nice smooth motion when recording fast moving shots from car, etc, which 24p IMO is not always great. slo mo is priceless to have ability to use. that is why i think 48p is ideal to shoot in all the time, because you can drop on 24p timeline and it throws away useless frames unless you need them! but so i dream!

    and my second film i imagine will not have that option since i shot with 24p

    (though i had the handy gopro shooting at 50p off the airplane). this is the kickstarter appeal video btw.

  • LPowellLPowell

    The GF2 and GF3 use the same image sensor as the GF1, which predated the multi-aspect-ratio sensor of the GH1. The GF sensor is fixed at 4000x3000 pixels and cannot be scanned at a rate faster than 30fps. The best results I got out of the GF1 were from my Fast Action 3-Frame GOP Patch, which records at a native 720p30 (or 720p25 in PAL mode) instead of the fake 720p60 mode. I believe that patch should also work on the GF2:

    http://www.personal-view.com/talks/discussion/223/gh1-gf1-g2-fast-action-3-frame-gop-patch-version-2-#p1

    Of course, since the GF1 lacked any 1080p modes, you'll need to provide your own settings for that.

  • rubberbanditorubberbandito

    i noticed that res Lee, totally makes sense. thank you, I'll check out that patch and modify

  • KeithLommelKeithLommel

    @rubberbandito: On GH2, getting 29.97p by using 80% variable recording speed mode gives better results than the HBR mode enabled by v1.1 firmware. This is because the 80% mode is based on the native 24p mode, where patch-makers have historically focused most of their energy on making the most optimized high image-quality patches. The HBR mode is really just the old 60i mode with the sensor readout lowered to 30 fps... Patch settings for the 1080/60i mode were never as good as the best 1080/24p mode, for a number of reasons (including lack of interest, but I've also read that the 60i stresses the codec harder, so you start bumping into limits and crashing the encoder sooner on 60i than you do on 24p as you tune the patches), so it follows that using the new HBR mode for 29.97p will give lower quality results than the 80% mode.

    The one caveat is that 80% mode does not record any audio at all. Your files will have nothing but silence. If you're relying on the in-camera audio track to sync to other cameras and/or your external recorder (instead of using a clapper, etc.), then you'll need to rethink your shooting/syncing procedure or accept the lower quality of HBR mode.

    Now that the new 3.64d ptools supports the HBR mode, and many people in PAL land are eager to use it for 25p, we'll perhaps see more attention devoted to optimizing settings for HBR that might narrow the quality gap between HBR and native 24p going forward, but at this time, if image quality is your priority, 80% mode is best.

  • rubberbanditorubberbandito

    thanks keithL. i can actually sync without a dual track but it is difficult and i would say too time consuming. i will either shoot both in 1080 29.97 or the question i wish someone would weigh in on is:

    can i intercut 25p footage from gf2 with 24p footage on gh2. will there be stutters and light flickers? or just light flickers in certain indoor lighting? any opinions out there from people that have done this on other than small tests?

    there is some interesting stuff on conversion here http://www.reduser.net/forum/archive/index.php/t-5704.html and http://www.gearslutz.com/board/post-production-forum/464825-25p-24p-blu-ray-audio-issues.html

    apparently there are two ways, interpret footage which will drop one frame and look jerky or decrease speed by 4% which is better but sound is off. most people will use gf2 as a b cam so sound probably is irrelevant. but i definitely see the light strobing when i film my computer monitor in 25p and none in 24p. this is because of the Mhz differences.

    hopefully this will help others that want to use both cams and shoot at 24p.

    i think i will settle on 29.97

  • rubberbanditorubberbandito

    I will ask once more now that I understand how GF2 works. I have GF2 and GH2. But I changed mind and want to shoot only in 24p on GH2 as primary. And I want to intercut shots from GF2. Is it better to shoot in 25p (on hacked GF2) or 30p? My workflow is to drop in Premiere Pro 24p sequence.

    I am thinking best bet is to drop 25p footage into premiere, then interpret to 23.9760, then put on timeline with GH2 23.976 footage and do not use Blend Framerate when rendering.

  • sshssh

    I got some great advices here: http://personal-view.com/talks/discussion/2956/how-do-you-combine-gh2-23.976-fps-footage-with-gf2s

    @KeithLommel

    "720/60p on the GH2 and cutting it with 1080/30p on the GF2. This matches resolution between the two cameras better, and gives you the added option of slow-mo on the GH2 footage."

    @balazer

    "I suggest making your target format 60 fps, which will support 24 fps and 30 fps cleanly"

    (Drop 24 and 30 fps clips in a 60 fps sequence)

  • bubbabubba

    @matthere & @unconsenting said run everything 25p to get a 25p master ..then converting that to 24p -was the answer. Anybody try that, yet?

  • rubberbanditorubberbandito

    why doesn't anyone approve of shooting in 25p and using the interpret footage as 23.976 in Premeire. Yes this slows footage down 4% but GF2 is meant to be a stunt and B shot cam to the GH2 (in my opinion) so in my case it will not be used for dialogue or sound capture. It seems like the best over workflow, rather than conversion which loses resolution and is a general pain. I am intercuting some gopro footage shot in 25 and 50p and you could see the frame skip when intercuting with GH2 when not first interpreting footage as 23.976 and 48, but if you take that step first seems very smooth to me. I don't like idea of shooting 720 60p because the trend now is 1920x1080 and in the next two years we will see lots of cameras pushing the 2500 and up.

  • rubberbanditorubberbandito

    yea, the other thing I notice though, just as important, is the color is very different. I love the cinema mode on GH2 but the GF2 modes do not look the same, the greens and other colors much brighter. anyone have a word on that? How to get the GF2 to look like GH2 in post, I use Premiere Pro, Magic Bullet.

  • sshssh

    25 fps solution is great. GF2 will look like crap @ 1080 unless you use it with longer (in my experience 35mm+) lenses for close-ups. Non-native glass helps, particularly older lenses that have lower contrast. You don't have much control over GF's output, you can however match it with GH's settings.

  • rubberbanditorubberbandito

    thx ssh here is a quick vid i made for an orphanage i am visiting, all the shots are with gf2 and 14-40mm lens with a 44mbit bit rate setting. the 3 or 4 shots starting with boy drying the dog are gh2 with 88mbit intra i hack. the image of gf2 is soft (but for $200 i am very happy), the gh2 crashed over and over and you can even see jagged lines in footage. i reset gh2 to 44. both are shot with 29.97. you can see the difference in color clearly, but i did not do any color correction, this was just a play test video. i will shoot next with the gf2 at 25fps and gh2 at 24.

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