Author Topic: Dual ISO - massive dynamic range improvement (dual_iso.mo) (Read 2222631 times)

Audionut · « **Reply #2475 on:** April 25, 2015, 04:51:49 AM »

Please keep issues regarding the 70D in the 70D thread. There's a reason it's still considered alpha.

winfel · « **Reply #2476 on:** April 25, 2015, 10:24:02 AM »

Very well. Just to inform you I tested some of my older 550d dual-iso-dngs and they behave and look similarly in Lightroom 5 and CC, so indeed it seems to be an alpha issue with the 70d dngs. Should have tested that yesterday. Sorry for that.

Myxir · « **Reply #2477 on:** April 25, 2015, 01:06:47 PM »

Quote from: Audionut on April 24, 2015, 01:13:06 AM

http://www.magiclantern.fm/forum/index.php?topic=10111.0
In the first post of that thread, also check the section entitled "Any recommended reading?". The DxOMark site will list the dynamic range for all tested cameras.

I'll have a look.

Quote from: Audionut on April 24, 2015, 01:13:06 AM

http://www.magiclantern.fm/forum/index.php?topic=10111.0
ISO 1600 > ISO 3200 may net you 0.4 EV on some camera when you are using standard image capturing. With dual ISO you shouldn't expect to see that result. Each ISO is only half resolution, so you throw away one full stop of (full) midtone resolution, to "gain" 0.4 EV of half resolution shadow detail.

Estimated DR gained:
100/800: 2.2 EV
100/1600: 2.6 EV
100/3200: 2.7 EV
(100/6400: 2,7, too?)

Quote from: Audionut on April 24, 2015, 01:13:06 AM

http://www.magiclantern.fm/forum/index.php?topic=10111.0
When you use recommended settings (100/800....100/1600), since the top couple of stops are generally white anyway, the resolution loss may not even be noticed. But when you start using extreme settings (100/3200), you're throwing away another full stop of midtone redolution, and this resolution loss is smack bang in the midtones. You probably want all available resolution for the midtones.

Where you use a low base ISO of say 100, the situation is probably even more dire. Here, you probably have your exposure (shutter/aperture) set for the base ISO. Since ISO doesn't effect shot noise, not only are those last few points of EV only half resolution, but they are also heavy with shot noise.

But what if I have an extreme (low light) situation where I may want to use not so usual setting? Such as 800/3200? Does it makes sense? And why do I get only ~0.5EV with that settings?

Edit: I see ISO 6400 is just 3200 with +1 EV digital ISO. So this would be an explanation (for me)...

Audionut · « **Reply #2478 on:** April 25, 2015, 01:26:16 PM »

Because the biggest gain is from ISO 100 to 200. Here you may gain 0.7-0.8EV. There's lots of noise at ISO 100, and the bump in sensitivity makes a big dent in the noise levels.

As ISO increases, the noise level is lower then the previous ISO, and so the reduction in noise level for each ISO bump reduces. As you note, when you go from ISO 800 to ISO 3200, the gain is only 0.5EV.

All other things being equal, you'll probably notice 0.5EV in the shadows. Higher ISOs also help to reduce any pattern noise (which are very visually distracting) in the images.

With dual ISO, 0.5EV in the shadows probably doesn't even come close.to outweighing the disadvantages. But it's your call.

Myxir · « **Reply #2479 on:** April 25, 2015, 03:06:14 PM »

From 400 to 3200 it's ~0.9EV. That should be noticeably.

I was thinking about using DualISO for some concerts or gigs. I know that I'm usually using very high ISOs, between 1600 and 6400. So I thought that I could use the second ISO to get the hang of high contrasts between spotlights and back/foregrounds.

Zanken already did this, but the links are broken and the pictures are gone. He had good experiences.

Quote from: Zanken

I'm a gig/event photographer experimenting with dual ISO. It's been great in environments where there is such a strong contrast for things like stage lights and flash work. A couple of examples.
...

Quote from: Zanken

The big win for event flash photography is getting more DR in the backgrounds. Especially events like festivals where you notice that background lights colour channels cap out really quickly and everything just looks really smudged. Dual ISO has helped me immensly shooting manual flash in a pinch in this environment too - my TTL flash was stolen a while back and I haven't been able to afford a replacement.

Most of the examples here seem to be scenes which makes sense. We've all seen overexposed skies and can appreciate at a glance how big an improvement we are getting with Dual ISO. I question why most people haven't really discovered it for portrait/event/performance/street style stuff where the loss of detail across the frame matters less and your RAW files has much more flexibility in what you get out of a shot that is just snapped 'in the moment.'

If there is one downside for me though, it's shooting an event (200-400 shots) and leaving them to brew overnight, ultimately costing me 60mb each shot. Here I was thinking that buying a 6D would be a good move to preserve HDD space - hah!

JoshuOne · « **Reply #2480 on:** April 26, 2015, 12:42:55 PM »

Ive read through this forum and the LR plugin one, I can successfully take a DUALISO raw phot, but for the life of me, I am not able to enable the raw video (either 1.0 or 2.0MLV) with dual ISO... I just skimmed back through this forum to see if I was missing something, if I am I was unable to find it. So... can I shoot dual ISO RAW video on the 5d mk2?
If I can, please let me know which settings to enable,as my experimentation has so far not revealed the proper setup, each time I enable dual iso, raw video greys out, each time I enable raw video, dual iso greys out. Thanks in advance for any assistance.

Licaon_Kter · « **Reply #2481 on:** April 27, 2015, 05:27:57 PM »

They don't disable on my M1, although maybe you'd want to read the description and enable HDR video instead

DeafEyeJedi · « **Reply #2482 on:** April 29, 2015, 11:21:05 AM »

70D111B Dual-ISO CR2's converted to DNG's is now finally readable in Adobe... Mad Props to @Danne & @nikfreak!!!

Marius · « **Reply #2483 on:** May 05, 2015, 10:42:43 PM »

Can any one give their experience how DualISO works in lets say weddings when you just take pictures of people moving/dancing, does it introduce any artefact for moving subject?

skrull · « **Reply #2484 on:** May 05, 2015, 11:17:18 PM »

Quote from: Marius on May 05, 2015, 10:42:43 PM

Can any one give their experience how DualISO works in lets say weddings when you just take pictures of people moving/dancing, does it introduce any artefact for moving subject?

If you cared to read how DualISO works you should know the answer. Your answer is in the first post of this topic.

mssrihari1 · « **Reply #2485 on:** May 07, 2015, 07:05:33 AM »

Trying to use dual iso on my canon 7d. I have enabled mlv raw, ettr and dual iso. Am trying to set an iso of 100 in the canon menu. But somehow its set to 3200. No matter how many times i do it, its set to 3200. There's a lot of banding in the resulting dng files. When i try to process it using the cr2hdr ui tool, the following message appears -

cr2hdr // Beta 1.4

Input file : M08-1022_frame_000001.dng
Input file : M08-1022_frame_000001.CR2 Canon EOS 5D Mark III detected Full size : 1728 x 972 Active area : 1728 x 972 Doesn't look like interlaced ISO
THE END

I am providing the link below for one of the frames in the video.

https://drive.google.com/open?id=0B_aIdQ5UVHpQUmN3N2dNbFZtV3M&authuser=0

Please help.

Walter Schulz · « **Reply #2486 on:** May 07, 2015, 07:10:15 AM »

Dual ISO video not supported for 7D and 50D:
http://www.magiclantern.fm/forum/index.php?topic=13597.msg131347#msg131347

mssrihari1 · « **Reply #2487 on:** May 07, 2015, 07:40:10 AM »

Oh! I missed that. Thanks for the update.

a1ex · « **Reply #2488 on:** May 09, 2015, 09:46:31 PM »

Updated cr2hdr with 70D support from nikfreak, and also with some fixes for future camera models.

At this stage, I think all major bugs from the 20-bit version were ironed out, so there should be no more reasons to use the old 16-bit one. Therefore, I've updated the Windows zip package with the latest version (also with latest dcraw and exiftool).

(note: the executable name is now just cr2hdr.exe)

DeafEyeJedi · « **Reply #2489 on:** May 09, 2015, 10:06:59 PM »

Great news, @a1ex!

Danne · « **Reply #2490 on:** May 09, 2015, 10:11:11 PM »

Awesome A1ex.

keepersdungeon · « **Reply #2491 on:** May 10, 2015, 12:19:36 AM »

Great thank u A1ex!

Macke1 · « **Reply #2492 on:** May 10, 2015, 02:16:00 PM »

Hello everyone! I have trouble shoot raw dual ISO. The problem is the pink dots that are common on canon 700d. I can shoot raw (no dual ISO) and get rid of the dots in MLVFS, chroma smothing 3x3 and bad pixel. I have in this example used the cr2hdr20bit. Hope someone can help me ?!

a1ex · « **Reply #2493 on:** May 10, 2015, 02:50:19 PM »

This problem is not yet solved. I have a sample file, but if you can provide more, it may help.

One or two unprocessed DNG frames should be sufficient.

Macke1 · « **Reply #2494 on:** May 10, 2015, 03:56:02 PM »

Sure, tell me what you need?! ok, how can i send it to you? pm?

Macke1 · « **Reply #2495 on:** May 10, 2015, 05:00:27 PM »

https://www.dropbox.com/sh/382k6362pfb6pz1/AABC5UBbMODwGZugaXkcbsa8a?dl=0

kichetof · « **Reply #2496 on:** May 11, 2015, 10:13:31 AM »

Mac version 0c08758

Thanks a lot a1ex !!

Danne · « **Reply #2497 on:** May 11, 2015, 10:23:40 AM »

Dreewling

Thanks Kitchehof!

DeafEyeJedi · « **Reply #2498 on:** May 11, 2015, 06:19:03 PM »

It's Kristmas all over again! [emoji3]

VanGogh7 · « **Reply #2499 on:** May 16, 2015, 06:52:58 PM »

5d Mark III

Dual ISO on, MLV Raw recording

and the latest:

-Nightly build
-raw2cdng.1.7.4
-cr2hdr

( Windows 7. 64 bit )

but the Dual ISO postprocessing isn't working.

Any suggestions?

News:

Author Topic: Dual ISO - massive dynamic range improvement (dual_iso.mo) (Read 2222631 times)