I've just reread all 9 pages of this post - phew!!
To the newbie this would still be very confusing as to the optimum settings.
The variables we are all talking about each directly affect the end result. Add one variable on top of another and the possibilities get mind-boggling.
We still don't have consensus on the best settings but our discussions & subjective tests on this forum is what makes the forum such a great tool. I'm trying to sum up mine & others testing conclusions so far, so have put it down here. Stop here if you expect a definitive conclusion at the end of this - I don't make one
I'm trying to get the theory correct before posting my conclusions.
...............................
Factors:
1. Brightness of day, cloud cover, subject colour & shadows (contrast) affects the dynamic range needed to record shadows & highlights. MP's sensor will only handle so much dynamic range, it isn't a high-end professional sensor. A sensor that will only record 8 stops of dynamic range will not record 12 stops of range not matter what you do. We struggle in Australia to get those lovely soft hues the northern Europeans seem to be able to capture - soft clouds are the free big diffuser in the sky. We get stuck with a huge big spotlight most of the time.
2. Choice of MP colour mode hugely affects how the "limited-dynamic-range 4.2.0-colour space" coming off the sensor is treated (via algorithm) before it is then compressed into the x.264 recording format (mp4/mov). Whilst Dji have given us colour mode tools so we can choose, I feel that most of these modes are designed for point & shoot users who just want a different look.
3. x.264 is excellent for giving apparent high quality visuals at low bit rates. It does this by throwing away masses of information. The x.264 GOP process in our MP workflow is what gives us our core flicker problem, on top of the limited bit rate compression that the MP encoding chip allows us to record in.
4. How you expose the footage has a huge influence on the end result. Is it best to lift your exposure to record detail in the shadows and throw away a bit of detail around the bright areas, or do the opposite? Is it best to expose evenly knowing darks and brights may not record everything. Or is it best to use dlog or cinelike hoping these algorithms will record as much dynamic range as possible and you'll be able to grade the picture back to normal. The small Go4 on-screen histogram is very hard to base exposure decisions on, and using dlog I appear to get top & bottom (within this histogram) areas of no image being recorded into. My background in film/digital producation tends to make me think the 4.2.0 colour space & x.264 hard coded recording bit-rates isn't capable of using these dlog/cinelike algorithms without compromising somewhere. When editing looking at the histograms of footage shot using dlog/cinelike it looks like I'm wasting about 25% of the recordable bandwidth. Top & bottom of histogram shows no information, meaning instead of recording colour information divided into 256 steps for each colour, I'm getting less than 200 - this increases the chance of banding. Others swear by dlog but for me the jury is still out.
5. Contrast, Colour values add another variable. Starting with a 4.2.0 colour space makes changing these values fraught with problems. Does reducing colour values in an already colour starved chain add to or reduce the original information coming off the sensor. Does reducing/increasing contrast make it harder to record dynamic range, and how is this affecting the colour profile selected. This to me is the last part in the puzzle to experiment with after other factors are worked out.
6. Sharpening appears to be added before(?) the colour space algorithm is applied, giving different effects to bright areas vs dark areas (water-colour-effect/overly sharp etc). Sharpening traditionally looks for adjoining pixels/areas contrast and enhances this contrast through quite clever algorithms, but can get ugly if too strong. If there is no discernible contrasty image in the dark areas you can't use contrast based sharpening. Tests I've seen here reducing camera sharpening, and then post sharpening have certainly reduced flickering but on all my different monitors made the image look very low resolution/quality. This has distracted my viewing experience way more than flickering.
7. Choice of post processing program (fcpx/neat/Davinci etc) and the various individual methods each have for sharpening/softening/temporal processing mean it's hard to compare each other's techniques on our own individual footage.
8. Youtube/Vimeo etc upload quality/compression-format and re-compression has a major impact on the quality/flicker. All our testing & subjective analysis should be done on pre-uploaded footage.
9. Our viewing monitors greatly affect how we perceive our tests. Looking at 4k/2.7k footage on a modern 55" TV is very different to looking at it on a HD/4k computer monitor. TV screens add masses of processing onto the footage in an attempt to make all the various qualities & resolutions fed to it via free to air, cable, internet etc look good and constant. Look at all the confusing names the manufactures use in their marketing materials discussing picture quality and processing "engines", every manufacturer has their own version. Computer screens can be quite brutal on video footage, making minor defects look major.
..............................................
Phew!! If you've got this far well done for perseverance. My post may be as complex to read as the previous 9 pages!!
My belief is DJI have no control over the image recording, they are locked into the sensor & video processing options by component manufacturers. It would be great if they would give us a little more technical information on their testing/reasoning behind the variables they have given us i.e. - why do we have cinelike & dlog - what shooting conditions are both algorithms optimized for etc.
Bottom line is we have an amazing little contraption capable of stunning results if all the variables line up. Just getting those variables right eludes us most of the time.
I am hugely grateful to all the various posters inputs & observations and certainly don't dispute anyones conclusions. We're all on the same side with trying to squeeze the best we can out of it.
Cheers.
Feel free to add to, correct or comment on any of the above.
