On 12/24/2019 8:28 AM, Wayne Shumaker wrote:
Thanks again Moose for taking the time to explain good points.
Thanks! I'm always interested in finding out what I'm talking about, although
that's not always possible. :-)
<> 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? No idea. Nothing like that has tickled my
antennae, but I may not be paying attention.
<>
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")."
This is just some random person giving what is clearly an opinion, as opposed
to actual experience. Nil useful info content.
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.
This strikes me as the main reason something like DRO could be useful. If the camera knew the exposure that would just
let recoverable Raw highlights kiss the top of the histogram, that would be a huge help; one more thing automated properly.
So many exposure control aids, histograms, flashing lights, zebras, etc., are derived from the JPEG that one becomes
suspicious. Yup, I use them, and they are useful, but not entirely reliable.
<>
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.
What I just said, about theory and logic vs. experience. Plus, all other things are seldom equal. For example, according
to the-digital-picture.com Review of the Sony-a7-III, it has lower noise on a -3 EV shot than the A7R III. No free
lunch here, as the smaller sensor sites extract their price. <https://www.the-digital-picture.com/Reviews/Sony-a7-III.aspx>
From the pragmatist's perspective, I want to see test shots showing a practical improvement from those precious two
bits. (No sarcasm. I've written code to store and extract eight binary bits of data in each byte of a database.)
Nattering Nabob of Nullity Moose
--
What if the Hokey Pokey *IS* what it's all about?
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