The Exposure Triangle Is Misleading And Unnecessary.

I think it's just that the same camera could achieve -5EV+f/2 and -6EV+f/1.4, since each change represents a halving+doubling, so a camera which requires f/1.2 at -6EV is a bit worse in the comparison.
Sherm

EV isn't directly related to the light in the scene.

Sounds like he is willing to accept dark review/OOC images, a little bit at all ISOs (-1 EC) and even darker when the resulting ISO exposure index falls above 3200. This would get him an extra stop of headroom safety at all resulting ISO settings, and even more when the setting would have gone above 1600 if it weren't limited.

I don't know if his camera has something like Canon's HTP, but HTP gives that -1EC under the hood without a stop of darkening for the default output, so you wouldn't see darker images until the ISO exposure index goes past a max ISO setting.

Perhaps it would be helpful to mentally separate empirical facts from people's recommended or favorite exposure/ISO setting strategies. If you fully understand the empirical facts without any "editorial" about application first, then you can listen to such editorial and recognize it for what it is - people's preferred strategies for managing risks, with different people having different priorities, but hopefully, on an accurate assessment of the empirical realities of the ISO settings.

The brightness triangle "works" to get brightness on-target with camera/software defaults (if EC is set for the key of the scene), just as a tricycle is guaranteed to stand up. The question is, do you need that, or need it all the time? The answer is no; it is not necessary to balance OOC image brightness to do photography, so breaking the lightness triangle open at the "ISO/exposure" vertex is possible, and possibly advantageous if you want more room for highlights or if you want less read noise, etc., than what you would get by prioritizing default brightness.

Many of the posters here probably dream of a mode of operation with cameras where you just choose your exposure time and f-number (or pupil size), and the camera just counts photons with no practical upper limit, and perhaps has an AI that analyzes the image and does a sought of auto-brightness for the EVF and OOC images, and assigns an assumed ISO exposure index in the metadata, but we don't have such cameras yet, so we do the best we can to emulate such a camera, which would serve many people well for most of their photography. Different people use different strategies, based on personal headroom vs shadow noise risk priorities.

Somebody referred to the function of the ISO control.
That should be "Functions", not "Function".

Don Cox

Most cameras already have an auto-brightness mode for EVF. The setting typically involves turning "exposure simulation" off. I wish all cameras would allow assigning "auto-brightness" to a function button.

It helps to preserve night vision, too ;)

That would not improve photon noise relative to exposure one iota. If there was always the same response, say always 2e for 1p, the photon noise would be exactly the same. If the response was inconsistent, like 2e 70% of the time and 1e 30% of the time (1.7e for 1p), then photon noise relative to exposure would actually increase. If there is readout noise in the system, then it will decrease read noise relative to exposure, which would be the main value of such a system. There are photosites like this; they are called photo-avalanche diodes. I believe that Canon just announced a consumer video-oriented camera that uses such technology recently, and as one might expect, the pixel density is relatively low to accommodate the spatial needs of such a diode. Of course, this isn't the only way to get to infinitesimal/irrelevant read noise; the projects that Dr. Eric Fossum has been working on create infinitesimal read noise with very small photosites.

I don't disagree with that. However, the best exposure for SOOC JPEG is rarely the best exposure for a raw file.

We are, truly, the inheritors of DPReview. A long and abstruse argument, some bits tending to acrimony, deeply divergent about a topic which only ever produces disagreement and never actually helps people expose their images correctly. I've not seen all the DPR favourite futile debates on here but the exposure triangle is one of them. We need to hope DPR doesn't sue for infringement of its IP with these long and unhelpful debates.

Are you certain?

A lot of useful posts in this thread are about debunking urban myths and "alternative facts." If you are willing to learn what happens when you press the shutter, you can gain something from this thread.

No mean hard-clipping response, but individual grains will only get photo-activated once, which is a sort of elemental clipping.

The same would happen with a one-bit digital sensor; you'd have a linear response right up to the point where the first photosite is hit twice, and can't change any further, and then as exposure continues, more and more photosites are hit and there are fewer and fewer that can still change.

I just did a simulation of a 100 kilopixel sensor that received 10,000 spatially random photons per frame in an animation, turning the canvas eventually from all-white to all-black, and it took about 120 frames before the last white pixel turned black. That means that it took about 12x the mean capacity of each frame to completely saturate it.