Fuji Processing raw x20 in camera...DR setting

Ian Knight

Regular
Mar 19, 2014
8
Hi, I have noticed that if I shoot at DR 400 or DR200 and process the raw file using the in camera RAW convertor it is possible to change the DR to a lower value. If I changed this to DR100 for example what would this actually be doing ?. If shot at DR400 the iso should also be 400. If I reduced the DR to 100 would this effectively give me iso 100 again?....
Thanks in advance.
Cheers Ian




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Mar 3, 2013
123
John Griggs
I'll take a whack at it. First, you may benefit from understanding how Fuji uses "iso-less" raw files at higher ISO. Take a look at Rico's article on ETTR and down it a ways he explains that: http://www.fujirumors.com/exposing-right/

Now that being said, I'm not sure how or at what ISO the X20 stops applying analog amplification to the sensor. Any shot made above that point is basically the same shot (subject to exposure changes) and the remaining ISO "boost" is done by the RAW converter.

For the area you're in, I believe that your RAW file should be slightly underexposed by the DR expansion. This gives you an opportunity to capture highlight detail in the RAW conversion.

Turning off the DR as you do the RAW conversion will change the resulting JPG most likely -- but exactly how is almost less important than how the result looks. Try it both ways and see which one you like.

Regardless, the RAW file has a certain exposure "baked in" right now and nothing you do will change that. You shot at DR400 and that affected what the camera captured into that RAW file (for instance, higher "ISO" and slight underexposure might be the case). What you do with in-camera RAW conversion will affect how the shot looks -- but doesn't change the ISO as such.

I usually tell folks this: don't worry too much about exactly what is happening. Learn the settings effect on how your image looks to you. Ultimately, that's all you need worry about.
 

Ian Knight

Regular
Mar 19, 2014
8
Hi,....thanks for the explanation ....it is much appreciated. .... I too subscribe to your theory of that it is what it looks like that matters!..... I was just curious about what might be actually happening if the dr is dropped when using the in camera RAW processor....cheers Ian


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Semion

Regular
Aug 11, 2014
18
Does DR really affect RAW file? DR settings may change the preview, but RAW itself should not be affected.
 
Mar 3, 2013
123
John Griggs
Does DR really affect RAW file? DR settings may change the preview, but RAW itself should not be affected.
Yes. The DR setting deliberately underexposes, hence the RAW file is affected. Your metering is altered by the DR setting, basically. The camera knows several "tricks" to maximize DR and if you will look up Rico Pfirstinger's articles (did I spell his name right?) they are some of the best I've seen of the system in general, and Fuji's in particular.

If you think about it, if you were metering in a "typical" manner where some highlights will be compressed or blown, how else could you get more dynamic range? The solution is -- to over simplify it -- "shoot dark and raise the shadows". DR expansion is even more clever than that about it, but that sort of summarizes the general idea.
 

Semion

Regular
Aug 11, 2014
18
My understanding of Rico's idea is that DR is kind of "post-processing" and does not affect the original metering. DR either push/pull your JPEG or works like a bracketing (which is the same, sort of), but the RAW file is a product of the "real" metering. That's why Rico recommends using permanent DR 100 with RAW.
 

Ian Knight

Regular
Mar 19, 2014
8
I guess this is why I posed the question. If the DR 400 is used for the shot is the base iso still 100 ?. Looking at rico's explaination it indicates that the base iso of 100 is retained and that the iso 400 setting that the image is shot in provides the 2 stops headroom for the highlights. After this the EXR processing then does its magic to blend the highlights through to shadows.
If the above is true then I would think that the RAW file is at base iso of 100 because the DR setting was engaged at the time if the image being shot .

Cheers Ian


Sent from my iPad using FujiXspot
 
Mar 3, 2013
123
John Griggs
My understanding of Rico's idea is that DR is kind of "post-processing" and does not affect the original metering. DR either push/pull your JPEG or works like a bracketing (which is the same, sort of), but the RAW file is a product of the "real" metering. That's why Rico recommends using permanent DR 100 with RAW.
DR has nothing to do with bracketing. But you are right you can get DR manually but you have to underexpose to capture all highlights for many scenes. Also reread Rico's articles on dynamic range where he shows how certain higher ISO settings can be used to get higher DR. The camera adjusts both exposure and ISO in DR mode to achieve the DR optimization.

So the short answer is it does affect the raw file. You may not SEE it in the EXIF data because the RAW converter may hide it from you -- but it is there. Go do some experiments with your camera snapping the same scene at all DR settings and examine your RAW data.

If you know what you are doing you can do as well or better than the DR -- if you know what it does. The most important thing is to ride the exposure comp which Fuji's make easy.
 
Mar 3, 2013
123
John Griggs
I guess this is why I posed the question. If the DR 400 is used for the shot is the base iso still 100 ?. Looking at rico's explaination it indicates that the base iso of 100 is retained and that the iso 400 setting that the image is shot in provides the 2 stops headroom for the highlights. After this the EXR processing then does its magic to blend the highlights through to shadows.
If the above is true then I would think that the RAW file is at base iso of 100 because the DR setting was engaged at the time if the image being shot .

Cheers Ian


Sent from my iPad using FujiXspot
I thought the X20 was x-trans and not EXR. Perhaps the X20 is different than what I am discussing. Might want to ask Rico directly.

Regardless, the RAW file is affected by DR settings -- primarily by being underexposed as you suggest.
 

flysurfer

Hall of Famer
Aug 31, 2011
123
It's nice to have the option to redevelop files with less highlight DR if the initial result looks too flat.

Obviously, in the age of isoless photography, we sometimes shoot on the safe side, playing it "too safe" by choosing DR400% when DR200% or maybe even DR100% would have given us a more pleasing result with "crisper" highlights.

Of course, the DR function is here so we can avoid exposing on the highlights. Instead, we can expose on the shadows, count "clicks" with the exposure compensation dial (to determine the difference between the correct exposure on the highlights vs. the correct exposure on the shadows, as described in my X-E2 ebook), then pick the appropriate DR setting. Adaptive ISO is such a great feature, but we don't need it for every single image (otherwise, Fuji could just use a fixed DR400% factory setting). So if the result looks too flat, we can reprocess the image with a less adaptive DR setting.

In the X20, picking DR400% simply means that the shadows are processed with (as least) ISO 400 and the highlights with (at least) ISO 100, with midtones and everything else occupying the ISO space in between. It's a tone-mapping curve. Fuji cameras are the only cameras on this planet offering 2 EV of adaptive ISO space, beating every other camera from every manufacturer in this regard. So even Nikon, Pentax, Sony, Leica and other camera makers that are also using ISOless sensors (mostly from Sony) can't really match what Fuji brings to the table.
 
Mar 3, 2013
123
John Griggs
The Fuji's, when I use them in JPG, definitely kick the butt of my old D7000. My X-E2 in particular makes me very happy with no "itch" to look for a better platform (at least for now, lol).
 

Ian Knight

Regular
Mar 19, 2014
8
I thought the X20 was x-trans and not EXR. Perhaps the X20 is different than what I am discussing. Might want to ask Rico directly.

.
Yes the x20 is x-trans and not EXR.( I also have an XF1 which is EXR. The DR settings work in a similar way to the X20 when used with a full sized 12 MP file ) .
Cheers Ian
 

flysurfer

Hall of Famer
Aug 31, 2011
123
DR100%, DR200% or DR400% depending on the subject, the lighting (brightness) and what ISO is required, anyway.

Of course, the typical/traditional "RAW shooter mode" suggests an ETTR approach with exposure on critical highlights, DR100% and several specific JPEG settings that I am discussing in my X-E2 ebook. However, this approach can make it difficult to actually see a subject in the EVF. The ISOless approach with a higher DR setting mimics the "Natural Live View" feature of the X30 and X100T that is now also coming to the X-T1.
 

flysurfer

Hall of Famer
Aug 31, 2011
123
Auto-ISO doesn't make a difference wrt DR. It's often quite practical, saves you changing ISO along with DR settings.
 

Ian Knight

Regular
Mar 19, 2014
8
I have just had a thought....it might be completely wide of the mark , but after re-reading Rico's exposing right article . It 0ccured to me that if exposing with dr400% and iso 800 ( or iso 400 with the X20) in jpeg there would also be an advantage in terms of noise. My reasoning is that if the DR is 400 then the shot is taken at base iso of 200 ( or 100 if x20) versus a dr of 100% and iso 800 ( or 400 if x20 ) because of the rise of noise casued by bumping up the iso .


Is this correct ?.

Cheers Ian
 

flysurfer

Hall of Famer
Aug 31, 2011
123
Not really. Noise should be pretty much the same thanks to the isoless sensor, as long as the ISO settings are the same. Of course, DR JPEGs have adaptive ISO, but that only affects the highlights, where there isn't much noise, anyway.
 

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