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

[stevefal]

Yes, feel free to write down the math for deinterlacing. Alternating ISO is trivial.

I now realize that alternating ISOs would likely affect midtones and cause them to shimmer as well if not de-interlaced. I suppose that simplifies the problem because the whole frame would need to be de-interlaced. So without having an alternating ISO video to play with, I tried an experiment in Premiere to see what it looks like to temporally smear video one frame. I did it by copying a set of clips, layering them on top of the originals, shift by one frame, and set opacity to 50%. The goal was for the output be the average of every two input frames.

The result looks good. Although there are temporal artifacts reminiscent of ML HDR video, static areas are crisp and actually cleaner because noise gets averaged down.

So the question is, couldn't such averaging of alternating dual ISO frames, whether performed by RAW2DNG or manually in an editor, treat the aliasing issue?

I'd be happy to experiment manually if I could generate some alternating ISO samples.

[a1ex]

@JackDaniel412: record 0.5 seconds of video showing the problem, and upload the RAW file. The DNG is processed and doesn't help.

@stevefal: this patch should alternate ISO exactly the way you suggested: http://acoutts.com/a1ex/alt_iso.patch

You can play with it, see if you get improvements, and I'll probably add it as an option in menu.

[Erik Krause]

Two examples with crops in extreme dual iso, 100-6400.

Very impressive! Could you provide the 100-6400 iso dng for download. I'd like to try for myself. I need to decide whether I buy a 5D3...

[Danne]

I,ll give it ago later. Will try to find a faster upload spot

[stevefal]

this patch should alternate ISO exactly the way you suggested: http://acoutts.com/a1ex/alt_iso.patch

You can play with it, see if you get improvements, and I'll probably add it as an option in menu.

I'm not set up to build - could never get my Windows setup to work. Also, I'm still stumped by the crawling aliasing artifacts in dual-ISO video. It looks like they are on a three frame cycle. Do these have to crawl? Even if the artifacts were flipping due to alternating ISO, my two-frame blending wouldn't work as long as the beats are crawling that way in the first place.

[a1ex]

I'm not yet sure when crawling occurs; it appeared in one test shot from Luke Neumann, but it didn't appear in all of my other test shots...

Maybe it has to do with FPS, PAL/NTSC or something like that.

[stevefal]

I'm not sure if we're talking about the same thing. I haven't seen one dual-ISO video where the alias beats aren't moving - self-crawling moire.

Doesn't it have something to do with the BBdd, dBBd, ddBB cycle I see when converting? Both are three frame cycles.

[a1ex]

Yes, you see it in the bbDD pattern. For me, only that one clip from Luke Neumann is crawling; everything recorded by me, and the Batman clip (also from Luke Neumann) are stationary. The clip from EOSHD is also stationary.

[stevefal]

Ok, I see a few that don't crawl. But everything I shoot crawls like crazy, just like the one above.

I'm shooting 1920x818, 23.976, C1, no FPS override, non-zoom.

[arrinkiiii]

If I got off my arse and compiled a 7D copy from the repo, I'd host it. I have no time for extra projects though and this would fall into that category. Hosting isn't a problem when I've pushed through 1 TB in 3 weeks off my home connection and Verizon hasn't cared...

Please, if you can make a compile version for the 7D. Want to trie    

[stevefal]

Another with crawl. Switch to 1080p and look at the bottom of the fence towards the end:

[a1ex]

Small converter update:

- fix crashes in cr2hdr with some unusual pics
- fix red "zebras"
- nicer highlight handling (aliasing artifacts should be blurred)
- minor tweaks

[Audionut]

- nicer highlight handling (aliasing artifacts should be blurred)

Old vs New.

[Canon eos m]

A1ex - I understand that the dual functionality is in development stages and hence most of the stuff will be things only developers can play with or comprehend. I am not a techie but try to keep up.

Have the raw2dng figured out thanks to Mixer2 and 1% from their contributions on the EOS M forum. Mixer2 has us really spoilt with his video casts and detailed explainations and steps.

Have the dual iso working on my 5D Mark III. Loving it.

Struggling to understand a major step. If I want to record in 100 /800 iso which one should I set on camera and which on the ML interface?

I first tried 100 on the camera and 800 on ML. But get better results if I do it the other way around. Is that the way this is supposed to work? Doing it the 800/100 way gives me better histogram accuracy and highlight /shadow feedback while recording.

[dubzeebass]

Another with crawl. Switch to 1080p and look at the bottom of the fence towards the end:

Hahaha, that's my video ... and my wife ... and my backyard! #winning

[dubzeebass]

Small converter update:

- fix crashes in cr2hdr with some unusual pics
- fix red "zebras"
- nicer highlight handling (aliasing artifacts should be blurred)
- minor tweaks

Is the EXE posted in the OP kept up to date?

[a1ex]

I first tried 100 on the camera and 800 on ML. But get better results if I do it the other way around. Is that the way this is supposed to work? Doing it the 800/100 way gives me better histogram accuracy and highlight /shadow feedback while recording.

Is there any difference in the end result? Can you post a comparison?

[enliten]

a1ex and stevefal... Are you guys talking about one frame, having line 1,3,5,7... at iso 100 and 2,4,6,8... at iso 1600, then on the next frame switching them?

if this is the case, couldn't you shoot at 60fps and and in post production get a 30 fps average of 2 frames, eliminating the moire?

let me know if i'm way off the mark here.

Also has anybody compiled the 7D binary yet?

-Ben

[Canon eos m]

Is there any difference in the end result? Can you post a comparison?

To my eye there was a difference - both in output and the way the camera reacted. Unless, by the time I swapped the ISO allocation, I had become better at playing around with this stuff and therefore began to imagine there was a difference. Will post the comparison tonight / tomorrow since I will have to look for a suitably contrastry situation to drive home the point.

By the way, I pointed the camara directly at the sun today and was able to get some awesome DR using the dual iso interface. The camera without the dual iso module activate threw some lovely blue clouds but a very shadowy foreground. 

Will post the results tonight.

[Danne]

Converted with the latest converter from Alex. Better sharpening algorithm which works best for most dualiso stuff. When converting the 100-6400 I get some artefacts pronunciation with the latest converter. Probably from the image itself.THere are som white minimal dots from the roompicture. You can look for yourself. Probably gonna use the older converter for bigger iso intervals and for most other shots using the new one.
Crap, I,m n the woods in the middle of the sun. Can,t get the pics right . One last try


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[a1ex]

The old converter from here was different from the one used for the previous set (the shadow artifacts are no longer there). Was it median6 (the very first version)?

I don't see any quality loss with the new converter. If anything, the sharpness was set too high when postprocessing the picture.

I'd also try these DNGs with this script. Would be nice if you could upload one, maybe when you come back.

Can you do now a comparison between ISO 100 and ISO 100/1600?

[Danne]

Hi Alex! I see what I can do. Used the latest converter from the zipfile in the first post. Soon getting back to civilisation to do some more comparison. Gettin on it asap, probably tomorrow

[a1ex]

This update should be pretty close to the ideal auto ISO option - for my needs.

https://bitbucket.org/hudson/magic-lantern/commits/373d8b5b0e69

You expose for highlights, it takes care of the shadows. It's pretty much impossible to do the other way, because you can't figure out how much a picture is overexposed if you look at the histogram.

[Danne]

New conversion tool from Alex works very good. Check out the difference and also the possibilities that the dualiso module gives.
Happy peeping!

Feel free to download the dual-iso cr2 rawfiles here. Both of them in 100-1600iso
https://docs.google.com/file/d/0B4tCJMlOYfirVWtwbDNpSXBMM2c/edit?usp=sharing


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[daancalo2013]

hello I have a 5d mark 3 and want to know how do I install dual iso, video tutorial please.