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

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

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Marsu42

Quote from: swinxx on October 04, 2013, 07:54:33 AM
so this could also be 800/1600.  am i right?

No, you're not, because the dynamic range gained from 100/800 (+3ev: 100, 200, 400, 800) is much larger than 800/1600 (+1ev) - ettr even shows this in the menu.

a1ex

800/1600 is fine, but it's only 0.5 stops of improvement. 800/3200 is 0.75 on 5D3. At this point you may as well just denoising the shadows a tiny bit (without getting any aliasing).

Here you can see the difference between ISO 1600/3200/6400 in shadows: http://www.guillermoluijk.com/article/isos5dmkii/index.htm

(hint: I can't see any)

But if that low light scenario also has some bright areas (think at street lighting), I'd go for 100/800, or 100/1600 if it's really dark, or try what ETTR suggests.

Here's an example:


First is ISO 100/1600; second is how it would have looked at ISO 1600 (it's not a real 1600 shot, but reconstructed from the dual exposure). It doesn't look bad, and the clipped areas are pretty small, but I prefer the first one.

And here's a night shot that did not require dual ISO according to ETTR, even though I was tempted to use it. Why? Because at 1/10 ISO 1600 there was no important detail overexposed (only some tiny specular highlights), and I don't think I could have used a slower shutter speed handheld. But if I would have allowed ETTR use a slower shutter, or asked it not to ignore any highlights, I think it would have chosen dual ISO.


ouuzi


swinxx

thx for your posting alex. i also cant see any difference on the iso shots 1600 3200 6400 from your link.  everything makes sense but i have to get used to it.. when you prefere 100/800 for a night scene with some highlight areas it means that you make no ettr without dual iso first, and then apply the second (lower iso) to get rid of the noise.. right?

and btw.. wouldn´t it be great to implement a "lock the 180degree shutter rule" for the raw video as an option for ettr, so that it only adapts the right iso for the scene. ?
when shooting video i always want my shutter to stay at e.g. 1/48 for 24fps..

thx sw

a1ex


Onoxyne

I try the dual iso with a 60D but my computer work with Ubuntu 12.04 and the compilation of cr2hdr dont work (problem with Makefile).
Someone have the .bin of this software ? And other to use this great module with Linux ?
I have download cr2hdr-static.linux.x86.2013-10-03-47b5360e8f49.7z found in the web but after unzip, I dont know what I can do with the file : cr2hdr-static.linux.x86.2013-10-03-47b5360e8f49.
Thank's for your lights...

Danne

Was out doing real estate photography and I decided to film two short sequences to see how dual iso holds up with today,s conversion tool. Also filmed a raw clip for comparison. Even though aliasing still exists and some jagged edges, It,s still eyeblowing to be able to get an even higher dynamic range than raw. I,ll try to find some time to get a moving picture.

Frame from raw 1920x1080p


Frame from dual iso raw 100/1600 (ISO difference : 3.98 EV (1577)


Still image (just for fun), three pictures, enfused to one.



Marsu42

Quote from: Danne on October 04, 2013, 09:29:41 PMFrame from dual iso raw 100/1600(or 800) Can,t remember

Another +1 for adding a xmp with the iso settings used :-o ... for bugtracking or recreating a scene it's important to remember how it was done, and this information simply isn't available unless you have a pencil and a piece of paper ready all the time.

a1ex

Sure, just find a command for exiftool that would add the ISO gap in a way recognized by Adobe software.

The second ISO is a little hard to guess with current metadata (some cases are ambiguous). Example: main ISO 400 and a gap of 2 stops - is it 400/100 or 400/1600?

The noise levels may be a good hint for solving the ambiguity (but right now we only have them in photo mode).

Danne

Actually @Marsu, my test was to see how well the latest cr2hdr holds up. It does a pretty decent job don,t you think? Also want to get some more dual iso filming going since I can,t find any good examples out there yet. Thanks for watching.

Updated the correct dual iso information, ISO difference : 3.98 EV (1577) 100/1600 that is :)
Also added a still image (third image) 3 exposures enfused to one. Amazingly the dual iso has a better range giving me blue skies in the windows

Marsu42

Quote from: Danne on October 04, 2013, 10:16:56 PM
Updated the correct dual iso information, ISO difference : 3.98 EV (1577) 100/1600 that is :)

Indeed, dual_iso is giving amazingly good results, and I have yet to see any 100/1600 shots from the 6d to show any noticeable problems - but I'll keep looking for them :-)

Quote from: a1ex on October 04, 2013, 10:16:25 PM
The second ISO is a little hard to guess with current metadata (some cases are ambiguous). Example: main ISO 400 and a gap of 2 stops - is it 400/100 or 400/1600?

* I remember you writing that, that's why I suggested writing a xmp in-camera when the accurate information is still available just like deflicker ... but if you think you can reconstruct both iso values from the cr2 I'll provide an exiftool cmd line.

* One "problem" cr2 from me: It's a 30sec long time test exposure with a 10x nd filter and shows sprinkles of various colors all over the place. Is this due to me using iso100/1600, or is this a cr2hdr problem which could be fixed with an anti-sprinkle algorithm? Unfortunately I didn't take a non-dual_iso shot to compare with this one. Here's the cr2 and a converted jpeg so you can have a quick look:

https://bitbucket.org/Marsu42/ml-mod6d/downloads/131003151753_D2#005512.jpg
https://bitbucket.org/Marsu42/ml-mod6d/downloads/131003151753_D2#005512.cr2

blahjovic

Does anyone know if medium or small raw files are supported with dual iso? I can't seem to find any info about it.
I tried a timelapse last night with small raw set on my 6D.  I get an error when converting using cr2hdr (latest from https://bitbucket.org/a_d_/magic-lantern/downloads):

Input FIle : DUAL6977.cr2
Canon Eos 6D detected
Full Size : 2736 x 1824
Active Area : 2736 x 1824
Error: dcraw output is not a valid PGM file

Thanks for any help and for all the work guys!

a1ex

If the menu allowed you to enable dual ISO with sRAW, this is a bug. Post some screenshots.

1%

The bug seems to happen if Q == sraw/mraw and you take a still in video mode. Or I guess on 6D if you left raw_rec on in photo mode (6D DOES need this if you want to monitor raw via wifi)

a1ex


painya

Sorry if this has been brought up, but I can't drag and drop because the cygwin1.dll is missing from my computer. Any thoughts? This is being shot RAW (.CR2) with a 6d.
Good footage doesn't make a story any better.

Marsu42

Quote from: painya on October 05, 2013, 08:35:13 PM
Sorry if this has been brought up, but I can't drag and drop because the cygwin1.dll is missing from my computer.

Your dcraw.exe, cr2hdr.exe or whatever.exe has been compiled with cygwin (unnecessarily, btw) and not mingw ... so now it needs this dll in the same directory or in the search path. Get the dll from http://www.cygwin.com/

Or use non-cygwin compiles, for example get a native windows dcraw here: http://www.fastpictureviewer.com/downloads/

painya

Quote from: Marsu42 on October 05, 2013, 09:52:11 PM
Your dcraw.exe, cr2hdr.exe or whatever.exe has been compiled with cygwin (unnecessarily, btw) and not mingw ... so now it needs this dll in the same directory or in the search path. Get the dll from http://www.cygwin.com/

Or use non-cygwin compiles, for example get a native windows dcraw here: http://www.fastpictureviewer.com/downloads/
The fast picture viewer will work for this HDR method? (with the add on of course)
Thanks.
Good footage doesn't make a story any better.

Marsu42

Quote from: painya on October 05, 2013, 10:28:15 PM
The fast picture viewer will work for this HDR method? (with the add on of course)

No, their site just happens to provide current x86 and x64 compiles of dcraw.

painya

I just started a thread on a seemingly too easy workflow. Mind checking it out to make sure it works for you as well?
Good footage doesn't make a story any better.

painya

Quote from: Marsu42 on October 05, 2013, 09:52:11 PM
Your dcraw.exe, cr2hdr.exe or whatever.exe has been compiled with cygwin (unnecessarily, btw) and not mingw ... so now it needs this dll in the same directory or in the search path. Get the dll from http://www.cygwin.com/

Or use non-cygwin compiles, for example get a native windows dcraw here: http://www.fastpictureviewer.com/downloads/
I install cygwin, and it still says I am missing the .dll. Any thoughts? I also installed the fast picture viewer. (I checked and found the .dll in the bin for cygwin)
Good footage doesn't make a story any better.



scrax

I'm using ML2.3 for photography with:
EOS 600DML | EOS 400Dplus | EOS 5D MLbeta5- EF 100mm f/2.8 USM Macro  - EF-S 17-85mm f4-5.6 IS USM - EF 70-200mm f/4 L USM - 580EXII - OsX, PS, LR, RawTherapee, LightZone -no video experience-

Marsu42

Quote from: a1ex on October 06, 2013, 02:03:00 PM
Broken links?

This really seems to be broken, maybe a bitbucket error/downtime - it should be there on my bitbucket download page https://bitbucket.org/Marsu42/ml-mod6d/downloads

If it continues not to work I'll re-upload them, maybe it's also the # in the name that confuses the system.