The Exposure Triangle Is Misleading And Unnecessary.

If you want a "lighter photo", you can just stick it in an image editor and make it lighter, or boost a slider during conversion. "More exposure" is primarily for "less noise"; not "more brightness". Brightness is a cheap parlor trick to meet human visibility requirements.

Not on any film camera that I own. During the last few years of film cameras, I think. But then, I normally loaded cassettes from bulk film, so maybe I didn't notice.
Don

Cassette DX coding started 1983.

I'm trying to wrap my head around how people are reading into things.

There's nothing "wrong" with that approach, but even with your need for an exposure index higher than base ISO, where you can't afford more exposure, you can manipulate ISO settings to increase headroom or decrease read noise. You don't have to vary the ISO from what the camera would choose, but you can if you want, if you are shooting raw and can adjust brightness in post-processing or conversion. If you know nothing about the raw data from your camera, then it might be wise to accept the defaults (other than adjusting "EC" for the subject key).

We're talking about a quarter of an electron. If that matters, we're not talking about what I consider to be photographic quality images.

I see the references in this thread to Nikon and Pentax manuals regarding ISO and exposure as defense of a misconception. For a topic such as ISO that even trusted sources frequently have a difficult time explaining in easy terms I find it ridiculous that the manufacturers have chosen to take the easy route as they continue providing what their engineers clearly know is misinformation. Do they perhaps assume that those that utilize the manuals are simply looking for a description of camera settings rather than for understanding of a concept?

Me, too. About 25 to 30 years ago, I was thinking about how to make images "appear" over time, so I took a source image, and a new, black canvas the same size, and randomly selected pixel positions and then checked the source image value at each of those pixels, and the higher that value was, the more likely (with a random() function) that the new canvas' pixel in that position was incremented by one level. The resulting animation of the new image showed Poisson statistics over time, although I did not recognize at the time that this is how photons arrive at the medium in photography.

I think so. When i worked at hp, we had a section in the manuals called "Theory of Operation". We taught that in training courses at Rolm. But I've not seen anything similar in camera manuals.

Yes, it is odd every time we log in for the last 2 weeks The Exposure Triangle Is Misleading And Unnecessary. is the highlight thread on top. In fact, could you remove that highlighted feature and simply leave the forums names? Just a thought...

Examples showing comparing different approaches, maybe. As they say, a picture is worth...

How many specific types of sources, or how many meanings?

There are only two broad categories of meaning; noise that is added, like garbage on top of a lawn (read noise, quantization noise, PRNU noise, dark current noise), and noise that is actually the "texture" of finite exposure/capture (photon shot noise).

"More trash" and "less grass", to use lawn analogies.

Again, I go back to my definition (exposure = light filtered by aperture filtered by shutter speed). That dictates what is presented to the image sensor (e.g. photons). Everything after that is essentially math (via amplification, positioning, counting, etc.). Modern image sensors tend to have at least two "conversions", one of which as you note occurs prior to the ADC. "ISO" is now trickier than a monolithic thing because of that. But "ISO" all happens post electron well.

I hear what you're saying, but it's hard for me to call a capacitor in parallel with the photodiode as being after the photodiode.

And both of the conversions of charge to voltage occur before the ADC.

It might be the first thing that most care about, but soon enough they will start to be bothered by blur and noise (or NR).

Sequence of events ;)

Do you take into account intended purpose? Not all photography is done to create large prints. Some purposes have very modest magnification requirements. Images generally appear less noisy, the less you magnify them. The noise that is decreasing by ~0.25e- in quadrature is post-gain read noise, which generally contains the most spatially-correlated and lowest-frequency noises of all noise sources, and spatially-correlated noise survives low magnification very well, in visibility. That is in quadrature, of course, and the actual decrease in post-gain read noise (in isolation) from ISO 500 to ISO 12800 is actually much greater than 0.25e-.

In a quick mental analysis of your graph, it seems like post-gain read noise is about 4.1e- at ISO 100, so at ISO 500 (assuming the camera gives the same headroom), I expect post-gain read noise to be about 0.82e-, and at 12800, 0.032e-. So, any large-scale correlated noise in the post-gain read noise is going to be about 25.6x greater at ISO 500 than at ISO 12800.

You also have the issue that the metadata in the raw file is most likely giving a more incorrect black point, in absolute terms (electrons), at ISO 500 than at ISO 12800, which causes false colors to become visible in the pushing process. We can see that even with pushes of only 4 or 5 stops with some cameras. Converters that allow you to move the blackpoints are nice, but they tend to have limited precision, with granularity dictated by the size of a raw level step.

I worked for Dymec/PAD/AMD from 1969 to 1973, when I left to get Rolm into the telephone business. I was a engineering project leader, engineering group manager, and engineering section manager, working for Gene Melesco (sp?) and Jim Pettit. I did the architecture for and led the HP2440A/HP2313A development. Hired by Dick Moss with an assist from Tom Whitney and Al Marston. I hired Ken Lavezzo away from AMD before I left to go to Rolm, then hired John Edwards. I was trying to hire Tom Saponas when John Young found out, called Ken Oshman, and told him to get me to lay off. Wouldn't happen today, but it was a club then. Later on when the smoke had cleared, I hired Jim Cockrum, Jack Lum, Tom Brigham, and several other people from hp.

The folks who'd been with Dymec a long time put their hp catalogs in their bookshelves upside down so the hp read dy.