How to get the best raw exposure, part 2

I think what you mean is "lowering the exposure".
If exposure is lowered, SNR becomes worse.
However "ETTR with ISO" doesn't always mean one is going to lower the exposure and "compensate" by raising ISO setting. They may want to keep the exposure and still raise the ISO setting until the histogram touches the right wall; in which case the may gain nothing in terms of SNR but pick a lot of avoidable clipping.

Dave, I'm thinking it's a joke or it's a trap. Hard to believe that Iliah would ask that question unless he's trying to dredge something out of @BurnImage ...

I think you are confusing ignorance with accepting the theory but steering it away from laboratory best in class results to actual real world use in the field for fast paced event photography and the like.

One has to balance real world usage against this nth degree of theory and come up with best practice in the field, which will vary by genre.

No, that's not the reason why DR falls as ISO climbs.

I don't see anything here that disagrees with what I wrote. It just a question of what the right words are.

So raising the ISO is effectively underexposure. Underexposure reduces SNR. This causes noise. DR is a measure from clipping to a given noise floor. If you increase noise you reduce DR.

Lightness/brightness are just words no one can agree to use in a standard way. When talking about the brightness range of the thing you are photographing I always called it Subject Brightness Range, but then no one else understood what that was!

Neither :)
It's a question to see how one understands things.

Iilah is always spot on with the theory, but never ever relates it back to real world dynamic fast moving photography. I know what the game is (I think we all do) and I'm ask probing questions to eke out best practice for the likes of events, weddings, street, sports etc.

Not everybody takes pictures on a tripod in a laboratory.......

No, it can be any exposure. Sometimes I raise both ISO and exposure.

Indeed. But I wanted to check my understanding :-)

I understand that you are suggesting that a low light events photographer does not benefit from lowering their ISO from 12,800 to 6400 where possible.

I answered it many times: I either preset everything (sport arena), or I use manual exposure + limited ISO auto.

No, and Bill Claff's data isn't the reason why why DR falls as ISO climbs.

Iilah, mayby; I'm not. But I try - part of it is remaining silent or asking questions when I'm not sure - and that happens a lot. And I never ask questions prefacing the question with "whatever the answer is my way of doing things is right".

I prefer a column.

And there we have it. Limited ISO Auto. I agree. Therefore, in those environments, ETTR is not irrelevant whatsoever. When shooting M mode with Auto ISO then using +EC of one stop is legitimate. It halfs (LIMITS) your ISO. With the flick of the EC dial I can half my ISO from 12800 to 6400 if lighting allows. The benefit of this approach is that I dont have to set a maximum auto ISO. I'm in control, with the benefit that I can still grab any shot that suddenly fall outside these lighting parameters.

Which camera?

Got me puzzled with that one, Iliah. I'm trying to imagine setting an aperture in the commonly-used Aperture Priority but watching the shutter speed going up when ISO is increased - which does not "keep the exposure" ... on my simple cameras anyway.

Sony A9II. I have mine set to aperture rear command dial, shutter front command dial. The EC dial is directly to the right of the rear command dial.

I'm in M mode, auto ISO, no upper limit set.

I shoot Raw. I use Zebras. I set the Zebras to "custom 109+"

My ONLY concern initially is setting shutter speed (slowest I can get away with for my motion blur requirements) and aperture (brightest I can get away with for sufficient dof).

My goal is to NAIL THE DECISIVE MOMENT!

I can then alter shutter, aperture or EC with my thumb and forefinger without taking my eye off the EVF, dialling in my settings as the shoot and/or lighting evolves.

The zebras will give me an indication if I can improve raw file quality by altering my parameters on the fly without taking my eye off the EVF.

For example, a simple one stop +EV will half my ISO. Or I can slow my shutter, or open my aperture. (The latter two options being the ones that put more light on the sensor). But halfing my ISO will give me a bit more DR in post.

BUT, that's IF time allows and it doesnt detract from the primary goal of NAILING THE SHOT.

Now, if anyone has a better way of doing it, for fast moving dynamic situations in the dark without missing a decisive moment then I'm all ears.

Scientific best practice is great, nailing the shot is even more important for me (and especially for my clients).