Wait, not always, some RAW I shot I get alternate frames, not 2 scanlines dark, 2 light
Seems there is a combination of settings that changes what the output is (alternate frames of different levels or switching levels on same frame )
OK I see the white paper (which is well writen by the way) says the rational for two scanlines is for debayering - makes sense
I stilll have not figured out why I sometimes get alternating frames and sometimes alternating scanlines
That's said -
1) don't think this is an option but for in theory for alternating frames mov mpeg 4 has a lot of difficulty usually with alternating levels (any intra-frames schemes), a good hack would be to store the alternate files in separate video streams. (or perhaps RAW on CF while mpeg4 on SD card - but with different exposure settings).
2) I see that it's true that changing the IS0 (as in dual ISO) appears to work for the noise as advertised. Does that mean Canon has some analog gain that this affects? Or is this because of the +0.3 ev I see in parenthesis?
3) There is also a rationale for alternate frames (one can play with our tool DE:Flicker High Speed
http://revisionfx.com/products/deflicker/ - Alternate Mode (Method 6.) with alternate frames mode to see - although not as is designed for this as there is no let's say tone mapping done...). It would be nice if in the HDR Video menu there was 3 options: (OFF, alternate frame, alternate scanline).
4) I do like that the live view alternates (the way it switches) otherwise it's a bit hard to set two levels (sde by side would work too, would maybe be easier to set focus). I am going to rent another camera next month or so to play some more, this is way cool. Although as said in the white paper 4 stops is usually good enough for realistic HDR at least until we can shoot 16b float but trying this with about 10 different things, I failed a few times. Maybe what is really needed is to have one capture for black level (no clamping even if noisy) and one capture for white level (no clamping at 1.0 except except maybe if you shoot the sun in frame or some specular high light reflections of the sun). I am mentioning as a potential idea for user interface for this as the sequence of buttons to press in what order is easy to mess up, would be more natural to look at a dark patch and press OK, then a very white patch and press OK and dual Levels recording is set. Seems since the two things compared are pretty much the same pixels looked at between frames restoring a relative level curve to the other is pretty reliable in a post process so it's fine to deviate from the classical photography capture model.
5) I note that the sample .dng file on first entry of this thread does not seem to load in Adobe CC 2014 CRAW reader (at least in AE). In general with this stuff it's probably not extremely useful to set the controls on the image reader itself though.
6) I also had the issue with the rental camera that often times the HDR video recording auto stopped after a few seconds. Someone suggested that it's a battery worn rental camera. I was wondering too if I set up something that made that happen.
Thanks,
Pierre
