Dual ISO - massive dynamic range improvement (dual_iso.mo)

Started by a1ex, July 16, 2013, 06:33:50 PM

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budafilms

Quote from: Pierre Jasmin on July 19, 2014, 05:25:07 AM
I am trying to see if this is expected

I rented a Mark III to test dual ISO video (with proper card...).

With normal video I get frame A a certain exposure, and frame B another one - and A,B,A,B alternating
With RAW I don't understand what I got

I have a frame with a certain exposure then the other frame has a 2 scanline pattern, 2 scanlines same exposure (light) followed by 2 scanlines (dark) and so on.  Here's a JPEG of what the bad frame(s) look like.

http://www.revisioneffects.com/bugreports/ML/testML.jpg

I would expect either alternating exposure on a frame or scanline basis but not every 2 frames every 2 scanlines
I thought it might be the converter from .RAW to .dng but I tried different ones with same results

This was for the most part 1080P 30 FPS, I did follow the instructions

So the first question is with RAW video dual ISO what should I expect?
Is there sample .RAW files somewhere I can go through same conversion workflow to see it's not me introducing this problem?

Pierre

Wich software are you using to convert all the footage?
Mystic? Raw2cdng? RawMagic LITE? Dual ISO has different software previous color correction.

Danne

Hi guys! Been playing with dual iso movies again and come to the conclusion that 3x mode is working really good for this. Having issues converting in lightroom using cr2hdr(Alex) tool plugin from Kitchehof. Getting a white bottom pixel stripe or something. This is more evident when selecting "fullres" in post processing within lightroom. Decided to test a few other converters.
As it goes, for now MLVMystic seems to have both fullres and with no white pixel strip giving good results. My wish is to get the "fullres" to work with recent cr2hdr within lightroom. Is it hard to change this behaviour in cr2hdr? What is causing this?
These are crops 1:1

Lightroom(Kitchehof) "Fullres" conversion with pixel stripe,


Lightroom(Kitchehof) "nofullres" Still a little pixel stripe at the bottom.


MLVMystic Giving good result without the any white pixel stripe


OSX_cr2hdr, an october version of the A.D mac drag and drop converter based on the cr2hdr before the white stripe problem


budafilms

Quote from: Danne on July 19, 2014, 09:37:01 AM
Hi guys! Been playing with dual iso movies again and come to the conclusion that 3x mode is working really good for this. Having issues converting in lightroom using cr2hdr(Alex) tool plugin from Kitchehof. Getting a white bottom pixel stripe or something. This is more evident when selecting "fullres" in post processing within lightroom. Decided to test a few other converters.
As it goes, for now MLVMystic seems to have both fullres and with no white pixel strip giving good results. My wish is to get the "fullres" to work with recent cr2hdr within lightroom. Is it hard to change this behaviour in cr2hdr? What is causing this?

Lightroom(Kitchehof) "Fullres" conversion with pixel stripe,
http://s2.postimg.org/6jd2pryft/Fullresblending.png
Lightroom(Kitchehof) "nofullres" Still a little pixel stripe at the bottom.
http://s2.postimg.org/5fsydtdsp/nofullres.png

MLVMystic Giving good result without the any white pixel stripe
http://s13.postimg.org/69st0bvhj/MLVMystic.png

OSX_cr2hdr, an october version of the A.D mac drag and drop converter based on the cr2hdr before the white stripe problem
http://s2.postimg.org/p1hfa0g7t/cr2hdr.png

Hi Danne, I see your photogram too noisy. I don't know if this is normal, but for professional purposes could be a big problem. It's an opinion. But maybe you have reason for do this.

Danne

The noise is irrelevant to my questions about the white pixel border issue and cr2hdr.
It is three times as noisy since I,m experimenting with 3xmode. It is also a crop 1:1

mihaii

I can't understand this (from the first page):

"Expose to the right for the lower ISO (usually ISO 100). Maybe darken 1 stop from there."

the metering looks like this   :  -2 ... -1 ... 0 ... +1 ... +2
Basically i should expose to the right (+1) and the darken 1 stop (go back?)



Let's say i have the sky and some shadow(y) parts

I usually use the spot mettering so I can get to pick which area i'm exposing for. Should I aim for the sky or for the shadow parts?

garry23

@mihail

If it helps, the way I use Dual-ISO is virtually always in conjunction with Auto-ETTR.

I use the SET setting for A-ETTR.

Thus my simple exposure workflow is this :

1. Comprise the scene
2. Take an A-ETTR exposure setting
3. Assuming you have also set Dual-ISO, say at 100/800 take your image
4. Ingest into Lightroom and use the CR2hdr plugin
5. Finish off in LR and Ps

Refinements will be setting Dual-ISO on every other image, and using the S/N setting, which I usually have zeroed out.

BTW here are a couple of iMages taken using A-ETTR and dual-ISO

http://photography.grayheron.net/2014/07/blue-hour-at-buffalo-thunder.html


Pierre Jasmin

Quote from: budafilms on July 19, 2014, 06:32:31 AM
Wich software are you using to convert all the footage?
Mystic? Raw2cdng? RawMagic LITE? Dual ISO has different software previous color correction.


You are correct I don't get the same result with Magic Lantern RAW - 1.2.0 and raw2cdn (windows)
With raw2cdn I get something more useful
I do get 2 dark lines, 2 light lines, 2 dark lines, 2 dark lines,...
Is this what I should expect?
It's fine if it's what I am supposed to get, just making sure what I am supposed to get

Pierre



budafilms

Quote from: Pierre Jasmin on July 20, 2014, 01:14:41 AM

You are correct I don't get the same result with Magic Lantern RAW - 1.2.0 and raw2cdn (windows)
With raw2cdn I get something more useful
I do get 2 dark lines, 2 light lines, 2 dark lines, 2 dark lines,...
Is this what I should expect?
It's fine if it's what I am supposed to get, just making sure what I am supposed to get

Pierre

Right! Have you change exposure, contrast, saturation and all that stuff in other software like ACR or DaVinci Resolve Lite (Free)?

Maybe you have read this: http://www.magiclantern.fm/forum/index.php?topic=7139.0

handbanana

So does dual ISO only work on the 5D3 for video? It's greyed out for me on the 50D in video mode :/

Pierre Jasmin

Quote from: budafilms on July 20, 2014, 01:22:34 AM
Right! Have you change exposure, contrast, saturation and all that stuff in other software like ACR or DaVinci Resolve Lite (Free)?

Maybe you have read this: http://www.magiclantern.fm/forum/index.php?topic=7139.0

Not what I am saying - I understand HDR...  see the link to the picture I posted earlier (2 dark lines, 2 light lines, 2 dark lines, 2 light lines)

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 )


Pierre Jasmin

Quote from: Pierre Jasmin on July 20, 2014, 01:55:25 AM

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


budafilms

You have a lot of ideas! You have a good level!
I think a Dev can read this and give you a good explanation.

I prefer shoot in Raw, it's something I can dominate and, maybe less dynamic range, but less noise too.

Using ETTR, it's a function that tell you if you need use Dual ISO or not. Maybe you can check that module, it's very, very good...

Pierre Jasmin

 
I have an answer for my own question (from another thread)
"
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?

"

A particular camera (sensor) has a point (like 3200 ISO) where it shifts from analog to digital gain.
i.e. so over 3200 one would be better to do it in post (at least if they shoot RAW)

Pierre


Attero

Hey Guys. I have a little Problem over here with Dual Iso. At first, u realy did a great job with this Modul, Big Thanks for that!

But now the Problem. I tryed the Dual Iso with the newest Version of Full Res Silent Pic (Imagine silent pics + 14ev dr...  realy awesome).

So i took a dual Iso image on the normal way. I got a simple .cr2 file as always. (left side)
After that i took a Full Res Silent Pic as a 14Bit .DNG with the new Modul (right side)



Both Images look OK for Dual Iso processing, or?(Yeha, the right pic is a little bit to bright, what ever ;) ) So i processed them both on the same way with cr2hdr.exe
But now look what i got after the process



The .cr2 image(still left side) looks fine but the Full Res Silent Pic .DNG(right side) looks very annoying.

Did i something wrong? Does some1 know's what happend here? Help pls!

barepixels

Attero, you should upload the file so the experts can take a better looks
5D2 + nightly ML

Attero


a1ex

Skip offsets are wrong in raw.c.

exiftool Dual_Iso_Silent_Pic.DNG -ActiveArea="50 142 3465 5344"

Attero


barepixels

I just tried ETTR and DUAL ISO with Full-size Silent MLV

out of 5 shots only one were made into DUAL ISO (with stripes) and it were process OK with cr2hdr.exe

the stripe were removed and file size went from 37mb to 43mb

Just for experimenting I tried to process the remaining 4 with cr2hdr.exe and nothing were change.

NOTE: I used the new mlv_dump to extract DNGs from the MLV

QUESTION: Why only one got made into DUAL ISO?

Here are EXIF info

1) 1/15 sec   F11.3  ISO 100
2) 1/1000 sec   F11.3  ISO 100   this is the ONLY file  have horizontal stripes (why is that?)
3) 1/1000 sec   F11.3  ISO 100
4) 1/1000 sec   F11.3  ISO 100
5) 1/166 sec   F11.3  ISO 100
5D2 + nightly ML

a1ex

Probably the image was not noisy enough to require dual ISO. You can try increasing the SNR limits.

barepixels

Thanks Alex for the explanation.  Now I understand.

I have decided NOT to use Dual ISO for Full-size Silent because

Shutter speed is erratic (some frame may get darken at the top)
Extra steps in workflow
Keep it simple stupid (KISS) policy
5D2 + nightly ML

a1ex

Erratic? The shutter speed behavior was explained in great detail...

barepixels

sorry wrong choice of word.  I meant not consistent.  for time-lapse we wouldn't want some frames have darker gradient at the top ...  flicker

dark, dark, dark, light, dark, light, light  ect...
5D2 + nightly ML

a1ex

Got it. I'm afraid it requires a custom deflicker algorithm that knows about this gradient.