I do have access to the entire standard. It uses the term 'value' which is a synonym to 'lightness'. Think colour spaces. The 'L' in Lab is 'lightness', the 'V' in HSV is 'value'. Both mean how light or dark something looks.
April 26, 2023
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They mean simulation of the look of the OOC JPEG.
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I do not think that calling it a "misnomer" without further explanation helps the owner of the camera read the manual for the camera.
Thanks for providing explanations.
For anyone els reading this thread, this explanation is especially good: www.rawdigger.com/howtouse/iso-is-seldom-just-digital-gain
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IMHO sometimes it's beneficial to open with a short statement to attract specific questions than with a lecture ;)
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It seems to me that the the introduction to the standard contains useful definitions. "EV (exposure value) units" is mentioned and the Canon camera metadata includes at least two EV numbers.
In the introduction and definitions section of the standard which is free to anyone, "value" is used for "standard output sensitivity" with this note:
"value" is also used in the context of the definition of "sensitivity setting":
Also:
Thanks again for providing explanations. I expect they will be useful to other readers.
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This is one reason why 'lightness' is a better word than 'value'. Each mention of value, you need to take it in context, so 'Exposure value' has a specific meaning, which isn't 'the value of exposure', whereas 'exposure index value' does mean the 'value of the exposure index'. In the context of the bit I'm talking about it says that the 'code value of 118 corresponds to 18% of the maximum final output for sRGB'. So what are we to make of that? An sRGB pixel doesn't have one 'value', it has three, R, G and B. So you have to interpret 'value' in the sense it has for colour spaces, which is as I said. It's clear also from other parts of the standard that is the only way of interpreting it that makes sense. To understand the standard you have to read it all and work out how it all fits together, it's not particularly well written and the choice of language not always the best in terms of making it easy to understand. So the rest of the bits that you're picking from the publicly available preview aren't really taking the conversation forward. The key thing here is how the standard defines the relation between exposure and lightness. That, and the proper definition of exposure, are the only bits relevant to this discussion.
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Nothing to do with total area. All per unit of area. Absolute is the number of photons per unit of area during the exposure, and relative is the ratio of absolute exposure to the recommended absolute exposure for the ISO setting or default processing for middle grey.