Rob Bannister Posted July 19, 2014 Share Posted July 19, 2014 Oh and as for the kinemini it has taken 9 weeks now to get my upgrade so I have no idea I have been told for the past few weeks im suppose to be getting it but it still has yet to be sent out from china....not looking good for them to support the professionals in the north american market. Whenever they decide to get their act together and get my camera back I will let you guys know.... Quote Link to comment Share on other sites More sharing options...
Jay Turberville Posted July 20, 2014 Share Posted July 20, 2014 Yes the issues came out when we told them on set to shoot a stop under. It pushed the codec too far and we were unaware that they were shooting directly to DnxHD and not to 444 DPX or raw. I think everyone was doing the change from something like the F35 to the Alexa. This was a few years ago it seemed everyone had this footage from episodic that you could not pull a clean key from. It is a lot better if you expose your GS one stop up but there still is macro blocking in these codecs...you can just make dealing with it a bit better...true 444 or raw is still the way to go. Somethng worth thinking about with raw from a CFA sensor is that while the demosaiced files may well be 4:4:4, the data contained within is not that good. Every four pixels only gets one red, one blue and two green pixels. So for green screen work the real data density is pretty similar to 4:2:2. (I say "similar' because the green in your screen isn't an exact match for the green filter on the sensor pixels - also, I think the green filters on the sensor pixels of CFA sensors tend to be fairly broad spectrum and more green/yellow - though that may vary from camera to camera.) If you use a blue screen, your mattes might suffer since you only get one blue pixel for every four image pixels. So anyway, I'm not surprised at all that the GH4 matte stands up well against the BMCC - given that the results are views at a resolution much lower than the native GH4 resolution. The GH4 records 2048 Green, 1024 Red and 1024 Blue samples at C4K. By comparison, the BMCC records only 1216 Green, 608 Red and 608 Blue samples in 2.5K raw. The GH4 has a clear advantage in total color samples. Basically, it has almost twice as many samples and at 1080p, it records a minimum of one color sample for each of the three primary colors - better even than 4:4:4.. Where the GH4 suffers is in bit depth and compression. Given a locked down camera with a green screen, the h.264 compression is probably really efficient. So it mostly comes down to the GH4's bit depth inferiority. So while the GH4 doing better isn't a numeric slam dunk, it shouldn't be a surprise either. Quote Link to comment Share on other sites More sharing options...
ItsMagic Posted September 26, 2014 Share Posted September 26, 2014 Andy- hate to be "that guy", but this clip doesn't prove a darned thing. You posted it earlier as well, and as someone else already pointed out there is so much motion going on that you wouldn't be able to spot a clean key versus a messy one in the first place. Not to mention it has been down sized to 480p. I mean, any HD camera downsized to 480p will work according to my explanation above about resampling. I'd say you could have probably shot this on an iPhone4 and gotten roughly the same results. Just saying. I agree. The keys in this video aren't exactly recommendations for the Canon camera's. They do look horrible. Even downscaled as they are. Andy, could you please post some full hd stills from your video to show some good chroma keys pulls? Quote Link to comment Share on other sites More sharing options...
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