How to get the best raw exposure, part 2

If you're happy with the raindrop analogy, you can safely skip the math at the end. It's there for people who want a quantitative feel for what's going on.

It is something that most people have to work with a while before it is fully internalized and you know what to do without consciously thinking about it. ETTR at base ISO is something that most folks can get their heads around without too much effort. The dim light situation is harder for some to get, and it is complicated by the fact that there are many ways of dealing with it.

All this is most difficult for people who started out with film, or those who have bought into the whole exposure triangle nonsense.

When the film is fresh, the meter is OK, scene to be captured is within 7-8 stops, metering technique is adequate (and for most part, from my lab days, it is hit and miss), and the exposed film is to be processed through manufacturer's first choice developer, close to the time of shooting - rating on the box can be taken as a very good guide.

The question of low light in itself is not more complicated per se. But the implementation is more nuanced depending on individual needs and priorities.

Basically it boils down to priorities. Do you want to aim for technically best raw files from an exposure point of view? Or the fastest way of working with minimal changes between lighting and shooting scenarios? Maybe a faster workflow and not changing settings leads to more decisive moment keepers and so on. Or a bit of both.

The logical next step is some threads about relating all this back to various genres and strategy options, with the pros and cons for each.

For one thing, it provides greater safety than full-manual in rapidly changing light. Set full-manual for the sun or the shade, and then all of a sudden you're several stops off if your next shot is in the opposite illumination, resulting in egregious clipping or excess read noise, with many cameras. With auto-ISO, you'll only be off by the range in which you might make "EC" adjustments but failed to do so, a much smaller range of error.

There is still the issue, of course, of having the Av and Tv values set in a way that the lighting forces clipping, and I am an advocate of camera options to raise shutter speed to avoid clipping with M mode or an otherwise M-like mode.

Given the persistent disagreement with my explanation of how cameras works occuring in this thread, the thought of doing something with far more moving parts and ill-defined boundary conditions fills me with despair. At the very minimum, I would expect it to be freighted with aggressively-voiced noise, and in the absence of threaded view, it would be hard for readers to perform the necessary winnowing.

It does the same thing for OOC JPEG lightness that automation does in Av, Tv, and P modes (but these may actually vary exposure to achieve that). The EC control also does the same, but it is not actually varying exposure, but ISO setting, and therefore, default lightness.

Another thing with M mode with auto ISO is using EC. EC will not put more light on the sensor, as you’ve already chosen your shutter speed and aperture. Light on the sensor is already set.

BUT

If my zebras give me an indication that it’s safe to apply 1 stop of plus EV then I will, especially in ultra low light. That can literally mean reducing my auto ISO from 12,800 to 6400.

For my particular camera, according to photons to photos, that reduction from ISO 12800 to 6400 gives me 1.4 extra stops of DR to play with in post if needed.

Does this trump using base ISO? Not from an optimum raw expsosure point of view no. IF that is your primary objective. Does it mean I can continue using live view without looking at a black EVF? Yes ! Does it mean I can use a “set and forget” mode whilst understanding the trades offs? Yes!

So, M mode with Auto ISO and EC can be a reliable and fast way of shooting. It always comes down to priorities.

I’m not so sure anyone disagrees with your explanations, they are facts. I’m personally always on a mission to relate this stuff back to real world scenarios and alternatives. Like I said to you earlier, we tend to agree, but from opposite directions 😂

There seems to be at least one person here who disagrees violently with some of my assertions.

Looking at the size of the world population, only one dissenter means you’re doing fine 😀

I don't understand this. In M you control shutter and aperture. That leaves only the ISO for the camera to change if you change the EC value and they go in the same 'direction'

Here are some of my attempts at that:

blog.kasson.com/a7riii/a7riii-exposure-strategy-manual-settings/

www.dpreview.com/forums/post/65368460

It should be pretty easy to write something similar for using auto ISO.

But look what he's done to this thread. Anybody coming in cold at this point would be overwhelmed by the back and forth, and would be hard pressed to find the nuggets that would be useful.

Not really. Let’s say I’m doing street photography at night in M mode with auto ISO. I’ve decided I need 1/400th to stop the motion. I also want f5.6 for sufficient DOF. So I’ve set this. I’m using auto ISO for convenience. And so I don’t have to disable or override live view in my EVF. The camera has selected ISO12800. If my zebras tell me I can use EC to increase 1 stop it immediately halves the ISO to 6400. This buys me 1.4 stops of DR in post.

It’s especially intuitive for me because my camera has a dedicated EC dial by my right thumb.

At least and at last, in this place, you can disagree without being muzzled or silenced for doing so! 👍

Teething problems. I’m sure some pinned definitive posts will follow. I’ve been guilty of being vocal. Maybe too much. But my intentions are always in the right place. My pet thing is relating the science back to real world shooting scenarios and finding that balance.

There will always be those that just want an argument for the sake of it. That’s forums for you.

It takes at least two to have a "back and forth". In the real world; some can do it endlessly, some will tire of it eventually, and some will eventually give up if ignored long enough. It probably works similarly in the virtual world.