The raw data that I showed wasn't processed into a monochromatic image. The raw data is a monochromatic image. Most raw files are TIFFs. And there is only one plane in the raw image data.
It is not a surface per say but where I want my white point to fall within the raw file, that white point may not even be in the scene. If that white point does not fall within the FOV I may even select an exposure that is even larger
I'm sure there are some good marketers who most probably are also ex-engineers but if you took a random sample of say 1000+ marketers from camera and lens manufacturers around the world and asked them what is "exposure", my experience tells me the majority would describe exposure with words to the effect of exposure being how light or dark an image is which is not technically correct.
If you also asked them to explain the relationship between ISO and noise, again my experience tells me most would describe it with words to the effect that the higher the ISO the more noise will be in the image which again is not technically correct.
seriously, i failed English at school, my daughter tells me all the time " Dad you are so hopeless at English" 😁 it was the motivating factor for her to become Dux of her schools. and im taking all the credit 😎
For maximising the quality of the raw data you need to maximise the exposure* within your DOF and blur constraints without clipping important highlights. In that case ISO is irrelevant for me, as long as important highlights are not clipped because I set the final image lightness in post, not in camera.
If I am ETTR'ing I lock in base ISO, all other times ISO is set to Auto for the above reason.
* exposure - amount of light striking the sensor per unit area while the shutter is open
** optimal exposure - the maximum exposure* within dof and motion blur requirements without clipping important highlights.
*** under exposed - more exposure* could have been added with the DOF and blur constraints still being met without clipping important highlights.
true, but we are looking for the surface thats going to give you a good start. here is the histogram of the surface in direct sunlight. its not 100% but boy its close.
What happens if within the entire FOV there is not an object that is lighter than that surface what could you do then, I would further increase the exposure
I don't need a surface to give me a good start. I just set the maximum exposure* within my DOF and blur constraints without clipping important highlights. The camera can set ISO where it likes as long as important highlights are not clipped. I then set the final image lightness in post.
You don't need any surface to do that. It's very straight forward.
* exposure - amount of light striking the sensor per unit area while the shutter is open
** optimal exposure - the maximum exposure* within dof and motion blur requirements without clipping important highlights.
*** under exposed - more exposure* could have been added with the DOF and blur constraints still being met without clipping important highlights.
Or heaven fore bid that there is an object that could cause clipping in the green channel like some leaves or grass, would you not have to adjust your exposure to eliminate that clipping. You do realize that you can have clipping in non white objects