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

[Danne]

check out my picture of a 100-6400 some posts up. Worked rather well.

[IliasG]

Thanks for the samples.

check out my picture of a 100-6400 some posts up. Worked rather well.

It did worked.
But the point is that the difference between 100-3200 vs 100-6400 is very small  in noise quality (0.09 stops in favor of 100-6400) while the difference in artifacts and resolution - detail is significant in favor of 100-3200.

Keep in mind that the result you see using 100-6400 is not only due to the cleaner ISO 6400 but also due to better processing by cr2hdr (black point calibration, channel matching ..) and a kind of denoise ( the data averaging by median filters) which get activated even when the ISO range is small.

You will need tests 100-6400 vs 100-3200 vs  100-1600 vs 100-800 (or 1600-3200 vs 1600-6400) combined with the appropriate for each case denoise by your raw converter to have useful data for a correct strategy for dual-ISO shots.

[Danne]

Of course one can spend a whole week comparing. Actually tried 3200 1600 and 12800.  100-6400 worked best. Fully aware of the algorithms with the converter creating the hdr and its importance. My tests so far are a blend of pseudoscience combined with vacation and just having fun
By the way Ilias, did you look at the noisetest dng,s?

[jpaana]

One small issue I noticed with the converter is that some tags, noticeably GPS coordinates, don't get transferred from CR2 to DNG, but adding -all:all to the exiftool command line fixed that for me:

Code: [Select]

diff -r 728e571a1276 modules/dual_iso/cr2hdr.c
--- a/modules/dual_iso/cr2hdr.c Wed Jul 24 16:58:18 2013 +0200
+++ b/modules/dual_iso/cr2hdr.c Fri Jul 26 22:42:56 2013 +0300
@@ -247,7 +247,7 @@
                 raw_info.white_level /= 4;
 
                 char exif_cmd[100];
-                snprintf(exif_cmd, sizeof(exif_cmd), "exiftool -tagsFromFile \"%s\" \"%s\" -overwrite_original", filename, out_filename);
+                snprintf(exif_cmd, sizeof(exif_cmd), "exiftool -tagsFromFile \"%s\" -all:all \"%s\" -overwrite_original", filename, out_filename);
                 int r = system(exif_cmd);
                 if (r != 0)
                     printf("Exiftool didn't work\n");


[IliasG]

..
By the way Ilias, did you look at the noisetest dng,s?

Yes, and in this comparison the single ISO shot matches better the Dual ISO one. The difference is smaller than with the first pair, no weird casts etc.

@ Alex
Do you consider instead of calculating "black data" in camera just save the side optically black pixels for better calculations later with raw2dng ?. For these black data 12bit are enough as it is now and if there is a possibility to subtract the black offset 8bit will be OK (for BL at 2048 subtract 2048-128= 1920 so 256 will cover the range +/- 128).

[budafilms]

Hi A1ex!
Your warning about use this method is strong than others advices. I will start a big project - movie - And I need to know wich is the real problem about work with this - I did some shots and no problem yet. So, it's Temperature? Card? Nikon people watching Canon Dual Iso quality?

 

[arrinkiiii]

@A1ex

I try the dual iso on the 7D but i take 1 or 2 pictures and show up the #70 error and didn't record any file to the card. Any ideas or solution for this?

Thanks for all, it bring a new breeze to the  7D owners.
 

[Audionut]

@A1ex

I try the dual iso on the 7D but i take 1 or 2 pictures and show up the #70 error and didn't record any file to the card. Any ideas or solution for this?

Don't bug the devs about my build.  I've created it for the sole reason of people with 7D's being able to test this feature.  It comes with no warranty or support (but I'll help where I can).

I don't know why some are getting errors.  I would suggest resetting the camera settings for a start, only shooting raw, no liveview shooting and only using base ISO's (100, 200, 400, 800, etc).

[feureau]

I don't know why some are getting errors.  I would suggest resetting the camera settings for a start, only shooting raw, no liveview shooting and only using base ISO's (100, 200, 400, 800, etc).

Using fresh installs from pelican's EOSCard, and no live view: my 7D crashed at ISO 800 and 400 and 100. The crash at ISO 100 is worst. The camera just died and removing and reinserting battery wouldn't revive it. Left it batteryless for a few minutes. Works again.

It would shoot a frame or two, then I could keep firing the shutter, but nothing gets written to card.

None of the crashes produces crash log though.

[arrinkiiii]

I don't know why some are getting errors.  I would suggest resetting the camera settings for a start, only shooting raw, no liveview shooting and only using base ISO's (100, 200, 400, 800, etc).

Sorry Audionut, thanks for the alert and for the build   

If my words don't belong were feel free to delete or to move to the post of the 7D (new ports).

In short words,

-My last picture that i take just freeze de camera, only the red light stay on (forever, evan if i turn of the camera) and in the upper scrren of the camera it's say "busy". I toke the battery off. Its possible to be a format card problem?

-Wend i manage to take a photo in dual iso, i review the photo in camera and i make a zoom to the maximum that the camera  can and i see only in the screen/photo lines. Do i need to convert this photo? Or is some error?

 Thanks one more time Audionut.

[Canon eos m]

Just checkout the dynamic range of the photograph (must be more than 14bit after some post processing):

http://www.flickr.com/photos/89977905@N05/9379336159/lightbox/

However, the RAW@DNG_Whitefix is causing some issues in the initial frames in video especially when the iso ratio is high (especially 100-6400 and higher). The alternating horizontal lines between the low and high iso show up even after rendering. Any idea what I am doing wrong with the workflow.

[Canon eos m]

An interesting article on the cost of going RAW for full lenght features (120 minutes of the final product):

http://www.redsharknews.com/post/item/885-preparing-to-shoot-raw?page=all

[ap1hk]

How did you compile this? I'm using gcc and getting all sorts of errors?

I downloaded the entire ML source and then go to the modules directory and compile the cr2hdr alone by "make cr2hdr".
It seems to work but I am not 100% sure. I compared with the result of wine cr2hdr.exe and didn't see much differences in the end picture so I assume this is going to work. I don't like using wine unless really necessary.

[Danne]

@ap1hk. See you got something going on mac. Why not share it?  A lot of guys out there in desperate need of a mac conversion tool
//D

[ap1hk]

@ap1hk. See you got something going on mac. Why not share it?  A lot of guys out there in desperate need of a mac conversion tool
//D

I am not sure if my compilation of cr2hdr is 100% okay. 

And cr2hdr is just a small issue but to get dcraw (and maybe exiftool as well) working on Mac, one has to install either Macport or Homebrew which actually could be very troublesome. However if one was using wine already then probably they have one of these unix ports installed.

Anyway, I don't mind sharing it if anyone wants it. 

[arrinkiiii]

@Audionut

Can you upload again the files in the dropbox (its empy) for the 7D users that solve the problem of crashing ?

Thank you 

I already manage to get yours last build and install but still crash with the 70error after a few photos and the pink/magenta still there wend use the cr2hdr.

What we can do?


(7D)

[xmd5a]

I think that pink highlights is a result of incorrect processing of clipped channels in some cases by cr2hdr.
"--force" option is needed because cr2hdr does not always detects that cr2 is interlaced. Option for reversed order of fields needed too.
One more comparison. No noise reduction (only "Remove dot noise" option), RPP. Aperture, shutter speed and processing settings are the same. Unbelievable clear shadows. (7D)
https://dl.dropboxusercontent.com/u/4624786/dual-iso_test2.1.jpg

[arrinkiiii]

I think that pink highlights is a result of incorrect processing of clipped channels in some cases by cr2hdr.
"--force" option is needed because cr2hdr does not always detects that cr2 is interlaced. Option for reversed order of fields needed too.
One more comparison. No noise reduction (only "Remove dot noise" option), RPP. Aperture, shutter speed and processing settings are the same. Unbelievable clear shadows. (7D)
https://dl.dropboxusercontent.com/u/4624786/dual-iso_test2.1.jpg

Its possible, with me is the same problem. In camera and computer the  preview of the cr2 of the photo seems to be ok, then wend use cr2hdr its just appear the pink/magenta in the highlights... In my case i think its not clipped channels, wend i toke my photos i have the preoccupation to not clip (overexpose) the photos but still appear the magenta/pink color in the highlights  wed use the cr2hdr.

[cosmo.lv]

Alex - how about 5D mkII is any chance to get dual iso on that?

[Danne]

Some random examples of dual iso cr2 images processed in lightroom. Nothing to compare to but the original exposure.

[sletts02]

I don't suppose this will work in 'Auto' movie mode will it?

[SuperJackRabbit]

really amazing!
and I wonder if the imagine could be as sharp as the original or not..

[Alex Roman]

Hey Danne, thanks for these; look awesome. Quick question: are they downscaled video frames or just full res pics? Also, which ISO interval on these? (artifacts are minimal)

thnx

[Danne]

Hi Alex. They,re fullres pics. Good stuff

[dubzeebass]

Feature request: can we have any Dual-ISO pictures prefixed with some sort of indicator so that it's easier to sort?  I took 400 pictures this weekend, 37 of them were Dual-ISO and it was a pain to go through and pull out the original CR2s.  If they're prefixed and sorted by Name, it'd be easier cuz it'd go PREFIX-FILENAME.CR2, PREFIX-FILENAME.DNG, etc.

Just a thought.