Print Page - Strange DNG

Title: Strange DNG
Post by: vstrglv on July 25, 2018, 06:23:45 PM

I tried to convert cr2 100/1600 to DNG with Barracuda GUI or simple dropping cr2 to cr2hdr.exe. I have got dng, but there is a very small difference from cr2 taken without dual iso

cr2 taken without dual iso (crop)

(https://thumb.ibb.co/cOTUpT/42917884964_174fbc3b02_m.jpg) (https://ibb.co/cOTUpT)

dual-iso-dng (crop)

(https://thumb.ibb.co/f7EzOo/43633884641_65446b4158_m.jpg) (https://ibb.co/f7EzOo)

dual-iso-cr2 (crop)

(https://thumb.ibb.co/jdgJG8/29764713088_1f47864e9b_m.jpg) (https://ibb.co/jdgJG8)

summe poetry (https://poetandpoem.com/summe)

Title: Re: Strange DNG
Post by: Walter Schulz on July 25, 2018, 06:41:46 PM

No untouched original files -> No diagnosis.

Title: Re: Strange DNG
Post by: vstrglv on July 25, 2018, 07:03:04 PM

Here you are:
No dual-iso https://cloud.mail.ru/public/NCAG/BitgNdmZN
Dual-iso cr2 https://cloud.mail.ru/public/MXoW/BUR4T2EQf
Dual-iso DNG https://cloud.mail.ru/public/NCsg/nsQgFndGW

Windows 7, cr2hdr on 04.12.2017

Title: Re: Strange DNG
Post by: Walter Schulz on July 25, 2018, 09:02:34 PM

Not an expert in dual-ISO but I'm pretty pleased with the amount of details in shadow areas in your DNG (compared to plain CR2).
And that's what (IMO) Dual-ISO is all about.

Title: Re: Strange DNG
Post by: Levas on July 25, 2018, 09:20:04 PM

Without post processing in a raw editor, there is not much difference to be seen between a normal cr2 and a processed dual iso dng.
The magic happens when you load them in a raw editor and edit them (Lightroom, RawTherapee, Dark Table etc.)
Load them in a raw editor and lift the shadows or push exposure on both, now try to see how much highlight detail you can get back etc.

Title: Re: Strange DNG
Post by: vstrglv on July 25, 2018, 09:31:56 PM

I see that if to lift the shadows there are more details and less noise. I thought that dng uses high iso in shadows without reducing an exposure.

Title: Re: Strange DNG
Post by: 50mm1200s on July 25, 2018, 09:48:37 PM

As @Levas said, the file has the information, but if you don't process you won't see it. I suggest you use the "HDR Tonemapping" from Rawtherapee 5.4. It's designed for these cases.
You should expose the lowest ISO to the highlights first and then use higher ISO for shadow details. You can automate the process using AETTR.
Also, if you are doing photographs of static objects and have a tripod, try HDRMerge (https://jcelaya.github.io/hdrmerge/) with 4 different exposures, output a 32-bit DNG and process on Rawtherapee with this "HDR Tonemapping" feature. This gives the best results you can get, as far as I know (unless this (https://www.magiclantern.fm/forum/index.php?topic=22564.msg204335#msg204335) could actually be implemented, still reading about this).

Title: Re: Strange DNG
Post by: vstrglv on July 26, 2018, 12:08:28 AM

Thank you for clarification.

Magic Lantern Forum

Using Magic Lantern => Post-processing Workflow => HDR and Dual ISO Postprocessing => Topic started by: vstrglv on July 25, 2018, 06:23:45 PM