Thanks again Moose for taking the time to explain good points.
At 12/23/2019 09:19 PM, Moose wrote:
>On 12/22/2019 5:03 PM, Wayne Shumaker wrote:
>>At 12/21/2019 10:39 PM, Moose wrote:
>>>On 12/20/2019 3:13 PM, Wayne Shumaker wrote:
>>>><>
>>>>I often check http://photonstophotos.net/ dynamic range curves. For
>>>>instance the E-M5 III peaks at 200, just as Ken mentioned, goes down a bit
>>>>at 100.
>>>>http://photonstophotos.net/Charts/PDR.htm#Olympus%20OM-D%20E-M5%20Mark%20III
>>>When I look at this sort of stuff, I usually wonder, oddly enough, what it
>>>means for practical picture making. My personal conclusion is often "damn
>>>little".
>>Pehaps, I still like to know the curve, but I'm not overly obsessed with it.
>>In the end you do what you need to get the shot.
>>
>>Cameras now have a built-in mode to take advantage of ISO-invariance. On Sony
>>it is called DRO - Dynamic range optimization. Basically it under exposes the
>>image and boosts it back up for the JPEG image output.
>
>That is only one part of it. According to A7 II Manual:
>
>"[D-Range Opt.]: By dividing the image into small areas, the camera
>analyses the contrast of light and shadow between the subject and the
>background, and produces an image with the optimal brightness and
>gradation."
>
>That says to me that it may not be just an overall adjustment? Or is
>aggregating by small area just to make the final calculation less onerous for
>the processor? Who knows. My answer is just D-Range Opt Out.
>>
>>Other cameras may call it something else. I have been attempting to find out
>>if it affects RAW files or not (on the Sony), which I assume it does not, but
>>may explain why I got poor results using the -EV trick, if the camera is
>>already also deciding to also do -EV with camera setting: DRO on auto.
>
>According to this site,
><https://photo.stackexchange.com/questions/80115/what-exactly-does-dro-do-and-how-does-it-work>
>
>"DRO is one of the few settings which indirectly impacts RAW files. While its
>designed as processing, which normally effects JPEG and TIFF files only, the
>camera adjusts exposure to have more dynamic range available for the mapping,
>often reducing exposure to get more details in highlights. If you shoot RAW
>and Manual mode though, DRO will have no effect."
I do remember reading that. If only shooting raw, I was not sure it still
applied. I will have to do some tests. Other cameras are doing a similar
technique:
"Sony calls its offering Dynamic Range Optimisation or DRO, Nikon?s is Active
D-lighting, Canon has Auto Lighting Optimiser, while Fujifilm has christened
its version D- Range."
Does Oly do something similar?
>It looks to me as though this effect may hold true for LVx settings, as well
>as Auto.
>
>In any case, it appears that you may indeed suffer from double EV dipping when
>using DRO. I have DRO set off, as I only shoot Raw. It seems that one might
>use one or the other, but not both.
Another online comment is the following:
"Be aware that, while DRO is pretty good in bright light (we used to do the
same thing during printing, back when pictures were taken on film, by dodging
and burning in), using DRO in a dark scene with bright lights will probably
give you a lot of noise in the darker areas ("speckles")."
>>Under exposing depends on the camera. Sony tends to preserve highlights
>>better than some other cameras, so I have not found under exposing to be that
>>much advantage - often finding there is too much noise in the shadows. I use
>>it when I need it, but more likely I will just boost the ISO. This is where
>>having 2 more stops on FF vs u43, to me, is an advantage.
>>
>>Generally, in lower light, the longer you can make an exposure the better the
>>noise. If you need to dial in negative EV to preserve highlights, that is
>>more of a camera dependent thing.
>>
>>What I have been attempting for proper exposure is ETTR - expose to the right.
>
>I was doing that before ETTR became a popular idea. Then ETTR became OUT. I
>don't recall why, but one risked not being heard if people reacted negatively
>to the acronym. I've gone right on doing what I might call ETRH (Exposure to
>Retain Highlights) :-)
Maybe the same technique but the idea of exposing to the right includes pushing
the highlights up as much a possible, without clipping, and as such, is pulling
up the shadows as well.
>A problem/advantage of the web is that many things never go away. The problem
>with the blog entry below is that it is seven years old. Sensor tech has moved
>on, and some of the generalizations no longer apply to at least some more
>recent sensor systems.
>
>>This requires the histogram be displayed, which can be improved with UniWB,
>>as the histogram is derived from the JPEG engine. To get better histogram
>>match for RAW files, getting a unity white balance helps. Jim Kasson has some
>>good info to get the best histogram:
>>
>>https://blog.kasson.com/using-in-caera-histograms-for-ettr/
>
>Too fussy for me. Just set EV to - 2/3 for the vast majority of shots, and
>Don't worry, be Happy!
>
>>Hence, when attempting to recover the shadows by boosting exposure in post,
>>it can lead to tonal range loss in the shadows. The image sensor + ADC is
>>linear, not logarithmic. So the number of bits in the shadow is reduced. This
>>risks loosing tonal variation,
>
>Yeah, words that are logically true, with conclusions that aren't borne out in
>practice, at least mine with recent sensors.
By sensor improvement, newer sensor ADCs now have more bits, which improves the
situation with tonal gradation in the blacks.
The GX9 uses 12-bit raw vs Sony A7R iii 14-bit.
Although not everyone has the visual tonal IQ that Ken does.
>>not to mention noise exaggeration.
>
>Per my reply to your 11/3 posts a few minutes ago, the excessive noise you are
>fighting is an artifact of processing protocol. Fix that, and you may be a lot
>happier.
I'll keep that in mind. Somehow I missed that reply. What you say makes sense
and I was less than rigorous with my experiment. Also my shot fell into the
"dark scene with bright lights" with DRO enabled, so first I need to repeat the
shot with DRO off.
Recap, Moose's replay was on 12/23, topic "Interesting denoise comparison"
suggesting to denoise before doing any exposure adjustments - that is, alter
the order of adjustments in post.
>Hold Onto Highlights Moose
While optimizing the Blacks WayneS
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