What is my ideal camera? A practical little cam that can do big stills (to crop in post), can handle natural-light without problems, can do videos with good bits for grading. Simply it doesn't exist.
Well, perhaps I don't agree with myself! Do you remember the old 5DM3?
Seriously, I've finally found out a very informative post by Sareesh Sudhakaran (
THIS) about apparent (!) advantages of 10bit over 8bit aquisition. Finally I've got the "technical and long-winded" answer I was searching for! (Thanks a lot!)
Really grossly: a noisy take wastes part of the potential range of bitdepth, and anyway codec compression reduces the actual difference between 8bit and 10bit. I hoped that noisy GH4's 10bit Prores was better than A7S' 8bit because I thought that a difference of 2 bits would have made the difference in post... I was wrong.
The real difference is between compressed codec and RAW. So, for my personal under-3K$-compromise-cams' challenge the contenders are:
1. A7S2: the best for low-light, 8bit codec surely breaks with heavy grading, 4K resolution;
2. BMCC2.5k: less noisy than the other BMCs but still noisy in low-light, 12bit RAW rocks in grading, 2K resolution;
3. 5DM3 (well... why not?): the deposed king of low-light, 14bit RAW w/ Magic Lantern super-rocks in grading, resolution sucks...
Ok, it's not sharp as HD should be, but even HD sucks compared to 4K, and even 4K will suck compared to 8K, and so on...
I was searching for a camera for video and big stills, for heavy grading and compositing, for low-light conditions: is Canon my winner?