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Does DRO bracketing produce EXIF data?

lew

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I just completed a shoot using dro bracketing. I assume 1 image favors shadows, the next mid-tones, and, finally, the 3rd favors highlights. Are the differences among the 3 recorded in EXIF or somewhere else? Is there any way to pull all of the "favors shadows" images out of the mix? Any way to tell which is which in post? (And, btw, am I correct in assuming that the 3 bracketed images would yield a good hdr composite in LR?)
 

bdbits

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A couple of thoughts.
* To the best of my knowledge, DRO only affects JPEG images. If you are shooting RAW it will have no affect.
* I can see DRO in EXIF using EXIFTOOL (Dynamic Range Optimizer is the label). I am not sure what value the DRO tag would have in it for the various settings since I have mine disabled.
* I do not know if the DRO bracketing is as simple as you say. Could be, but I do not know.
* I think DRO and HDR are complimentary ways of achieving a similar end. I am not sure combining them is going to give you the best result. It would be far more typical to use exposure bracketing for use in HDR in post.
* If you are mainly trying to enhance shadows, have you simply tried pulling them up in post? Sony files for most bodies are very malleable and that may be sufficient. I often expose for highlights and pull up shadows after and find it works really well for the most part, even on an older A7ii. I shoot RAW and use Capture One which may explain part of that I suppose.
 

dbmiller

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I don't have my camera with me at the moment to check on the EXIF data. I think there's an EV field, which might be useful.

While I know you can change the order of exposures (+,0,-) or (-+0), for example, there isn't anything in the filenames to show which is which. But it's pretty obvious from the thumbnails when a bracket of shots appears.

The number of images needed for an HDR composite, and the EV separation required will vary depending on your subject. If your subject is very bright overall, you might want to shoot at -2x,-x,0 instead of -x,-,+x. If your subject is very dark, with little highlights, you may shoot at 0,+x,+2x.

A single RAW file can often be turned into an HDR-like image since the Sony sensors are quite capable of pushing the shadows (Technically, that's just "tone mapping", not true HDR). But if your highlights are blown, there is nothing you can do to recover. If you have one of the models that will allow you to expose for the highlights, that could be quite useful.

A bracket of three is probably sufficient for viewing on a monitor, but if you're going for a nice big print, you may want to use a 5-shot (or 9-shot!) bracket instead to give you smoother gradations.

Do some googling and check out some HDR tutorials. You can then decide if the processing time is worth it to you, or if the in camera Auto HDR is "good enough".
 

bdbits

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You will find it debated in some places on the internet, but I am confident DRO does not affect RAW images. That it still takes multiple images does not mean it is applying DRO. Jim Kasson knows more about this sort of thing than I ever will, and he says DRO does not affect RAWs at least for the A7ii I have, but I doubt this would change in later models: https://blog.kasson.com/the-last-word/does-dro-in-the-a7ii-affect-noise/

EXIFTOOL is a command-line tool, probably the most comprehensive of its kind. On Windows it will create a shortcut on your desktop that lets you drop an image file on it to display all it finds. There are 3rd-party graphical interfaces but I don't use them. There is a version for Mac, too, but I cannot really assist you with that. https://www.sno.phy.queensu.ca/~phil/exiftool/
 

lew

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"You will find it debated in some places on the internet, but I am confident DRO does not affect RAW images. That it still takes multiple images does not mean it is applying DRO. Jim Kasson knows more about this sort of thing than I ever will, and he says DRO does not affect RAWs at least for the A7ii I have, but I doubt this would change in later models: https://blog.kasson.com/the-last-word/does-dro-in-the-a7ii-affect-noise/"
-> Surfing some Sony pages, I came across the following:
"The D-Range Optimizer function instantaneously analyzes the captured image data and automatically corrects for optimal exposure and tone reproduction. Often when taking backlit scenes, the subject's face or other areas in shadow appear darker in the photograph than they appear to the human eye. The D-Range Optimizer function discriminates between different conditions for the photographed scenes automatically corrects the gamma curve, exposure level, and other parameters to remove portions that are darker than they would appear to the human eye. "

Assuming this is so, it'd work fine with RAW images.
 

Kirkp

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For the a6000 Sony makes it clear that HDR settings don’t affect the raw file.
http://docs.esupport.sony.com/dvimag/ILCE6000_guide/en/contents/TP0000314497.html
I can’t find a definitive statement for that camera about DRO, but I’ve found some Sony documentation stating that raw files are always “undeveloped” images (i.e., pretty much straight out of the sensor). However, the exif will record the camera setting. That’s the same for other processing such as lens vignetting and distortion correction.

Also, “DRO Bracketing” takes three shots, one with each DRO setting. They are separate images, not mapped into a single image as for HRO. The jpeg will be different for each, but I think the raws will all be identical except for the exif, which may show a different DRO setting.
 
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Tipton

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Assuming this is so, it'd work fine with RAW images.
For the a6000 Sony makes it clear that HDR settings don’t affect the raw file.
DRO *shouldn't* affect the RAW file, because then it's not a RAW file, by definition. All a RAW file should be, is the readout from the sensor, plus the jpg preview and some metadata.
 

lew

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* I think DRO and HDR are complimentary ways of achieving a similar end. I am not sure combining them is going to give you the best result. It would be far more typical to use exposure bracketing for use in HDR in post.

Not entirely. DRO bracketing produces multiple raw files from a single exposure, HDR requires multiple exposures. DRO, therefore, works on the street, HDR on the tripod.
 
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That intrigued me enough to go look what my camera will do with this DRO bracketing. The A7Rm4 indeed produces 3 raw files from 1 single exposure; just guessing that older cameras work similarly but I'm too lazy too check what my A7 will do.

So what are the differences in the raw files?

Imported into Lightroom and have Lightroom generate previews:
   ---            

All the raw files look the same, so very probably the raw data aren't affected.

Previews as shown in macOS Finder:
   ---            

Never mind the green check marks, these are from Dropbox. The previews contained in the raw files are clearly different, shadows are increasingly pulled up.

Installed Sony Imaging Edge and exported jpegs from the raws in that program. Jpegs shown here in Lightroom for convenience:
   ---            

The jpegs differ from each other but not as much as the previews in Finder. While editing, I could see the editor build up a lesser amount of shadow pulling than that of the preview. The dynamic range optimization in Imaging Edge Editor shows different settings for each raw file. Handmatig means Manual and the Hoeveelheid (Amount) is 50 for the last file as shown here; amounts for the other files are 10 and 30 resp. Did a quick glance with RawDigger over the EXIF data but didn't see immediately where this info resides.
   ---            


So I'm almost certain that the raw data isn't affected because Lightroom generates identical previews for each raw file. Sony's own Imaging Edge Edit program probably uses EXIF metadata to set an amount of dynamic range optimization, which looks a lot less heavy-handed than the previews in Mac Finder which are generated by the camera.

I'm always very alert when there's suspicion of the camera altering raw image data but that doesn't seem to be the case here.
 

lew

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My findings, too. This being the case, however, shouldn't DRO bracketing be "OFF" or not available when one chooses to output ONLY RAW files? Taking up storage and io time for 3 large, identical files doesn't make any sense to me.
 
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My findings, too. This being the case, however, shouldn't DRO bracketing be "OFF" or not available when one chooses to output ONLY RAW files? Taking up storage and io time for 3 large, identical files doesn't make any sense to me.
That's probably why I never bothered to use DRO bracketing. You could argue that nothing is lost in producing multiple raw files with identical image data, if someone chooses to do so to get access to Sony's image processing wonders :).
 

dbmiller

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My findings, too. This being the case, however, shouldn't DRO bracketing be "OFF" or not available when one chooses to output ONLY RAW files? Taking up storage and io time for 3 large, identical files doesn't make any sense to me.
That's probably why I never bothered to use DRO bracketing. You could argue that nothing is lost in producing multiple raw files with identical image data, if someone chooses to do so to get access to Sony's image processing wonders :).
Does seem odd, but yeah, you told it to take a bracket, and the RAW files do contain the info needed to change how the RAW file is processed. But I guess most editing programs don't know what to look for, nor what to do with it, so all the shots in the bracket get processed the same and don't look any different.

I also imagine that the previews in camera, and before you import them anywhere would show the DRO processing, but you'd lose that as soon as the software generated its own preview from the RAW data, ignoring the DRO EXIF data.

Shooting in RAW+JPEG, you'd again get three identical RAW files except for the EXIF info (and embedded JPEG preview). But they should line up with the generated JPEGs. And you'd have the JPEG to compare with when trying to get the RAW to match. Still... Highlight and shadows sliders aren't that hard to manipulate.
 

bdbits

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I believe the algorithms that apply DRO are protected intellectual property owned by Sony. Sony's own editor used to be able to apply DRO to a RAW, but nobody else would be legally able do this. I am not sure about the current edition of Imaging Edge as I do not have it installed at this time.
 
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