Strange DNG

Started by vstrglv, July 25, 2018, 06:23:45 PM

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vstrglv

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)



dual-iso-dng (crop)



dual-iso-cr2 (crop)



summe poetry

Canon 5D3,1.1.3; Canon EOS M,202,  CF-SanDisk Extreme PRO,160MB/s, 256GB, SD-SanDisk Extreme Pro, 170MB/s, 128GB.

Walter Schulz

No untouched original files -> No diagnosis.

vstrglv

Canon 5D3,1.1.3; Canon EOS M,202,  CF-SanDisk Extreme PRO,160MB/s, 256GB, SD-SanDisk Extreme Pro, 170MB/s, 128GB.

Walter Schulz

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.

Levas

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.


vstrglv

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.
Canon 5D3,1.1.3; Canon EOS M,202,  CF-SanDisk Extreme PRO,160MB/s, 256GB, SD-SanDisk Extreme Pro, 170MB/s, 128GB.

50mm1200s

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 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 could actually be implemented, still reading about this).

vstrglv

Thank you for clarification.
Canon 5D3,1.1.3; Canon EOS M,202,  CF-SanDisk Extreme PRO,160MB/s, 256GB, SD-SanDisk Extreme Pro, 170MB/s, 128GB.