Exposure is not how dark or how light an image looks!

i dont know of any camera user manual saying any different ,its been around for decades. If you know of any camera manual that says exposure is just shutter speed and aperture i be interested.

quote from the latest sony manual

"In the auto shooting modes and P/A/S-modes, the automatic exposure (AE) function is activated. As a result, the camera will determine the optimal exposure and set the aperture, shutter speed, and ISO sensitivity accordingly. By using this AE function, you can shoot photographs with appropriate brightness, automatically determined by the camera."

Tonality ?

There are also the expressions "High key" and "Low key". (But not "medium key".)
Don

You're exactly right. On more than one occasion, I've reminded colleagues who were getting excessively worked up about a problem, that we're not dealing with life or death issues and that this too shall pass — whatever this too of the moment happened to be. So far we've had grave, dangerous, and toxic applied to the discussion, but I haven't seen much to actually fear.

You won't find dither, ADC inputs, or any number of other things mentioned. They're ignored because they are beyond the scope of the article and its intended purpose and audience.

Sounds like he knew his audience and the broad concepts he was trying to introduce to them and doing so in a way they could initially start to grasp.

so all camera companies are wrong ? whats correct beef burger or ham burger ? fish and chips or fish an french fries [😉😁 accelerator cable or throttle cable . brake line or brake tube [😜

If they say ISO is a component of exposure* then yes, they are wrong. The effect of ISO is applied after the shutter has closed and no more light can reach the sensor. So ISO cannot be a component of exposure*

For example:

For a given scene and lighting -

A. f/8, 1/400s, ISO 200

and

B. f/8, 1/200s, ISO 100

will both output the same image lightness but the ISO 200 shot will have had only half the exposure* of the ISO 100 shot and so will have more visible noise in the shadows because of the lower SNR resulting from the smaller exposure*

Exposure* and image lightness, although related, are two different things and not 2 different names for the one thing.

It's when people use exposure* and image lightness interchangeably as if they meant the same thing that they often get themselves in a twist, especially when I tell them I can change the image lightness in camera while keeping a constant exposure*

What is the definition of the word 'exposure' you use when you use it in sentences?

* 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.

In perhaps a vain mediation attempt :) : Can we agree that shutter-speed and aperture affect the number of photons hitting the sensor, but ISO does not?
Cheers!
Jerry

Artfully conceived and expressed. I'm gonna tuck this one away under the cranial cap.

You admit that you don't see statements like
"A photograph's exposure determines how light or dark an image will appear when it's been captured by your camera. "
"ISO speed: controls the sensitivity of your camera's sensor to a given amount of light"
"higher ISO speeds dramatically increase image noise"
as fundamentally wrong.
Ironically, the topic here is "Exposure is not how dark or how light an image looks!"

We can, if we realize what happens when we set ISO and let the camera choose exposure parameters (shutter speed and aperture) based on metering and ISO setting ;)

The concept he was introducing was not germane in the world we live in. Maybe in an alternate universe where cameras had FWCs of 200000e- and 8 bit ADCs, it would be germane. But it's a red herring.

And completely unnecessary. You can motivate users to move in the direction of ETTR at base ISO simply by explaining how photon noise works. That has the advantage of truth: it is the dominant noise contributor for most photos at base ISO. And it has the additional advantage that, unlike ADC precision, it is a consequence of physics and won't be affected by advances in the CMOS technology that keeps the same broad architecture.

The "half the counts are in the top stop of the image histogram" argument should be consigned to outer darkness, as far as beginners are concerned. It's possible to put some cameras into some modes where, at some ISOs, there is inadequate dither, but that's not the common use case.

By the way, I once had a Hasselblad H2D-39 that carried dither to a ridiculous extreme. It had a CCD sensor with off-sensor 16-bit ADCs. The 5 LSBs were pure noise.

I think we can agree, yes. In physical terms, changing ISO’s will vary the #photons hitting the sensor, FOR a given shutter-speed & aperture (assuming, as you said, that the camera is choosing 1 or both of shutter & aperture).

I’m sure you’d express it in more technical terms (commensurate with your deep domain expertise). But, partly, I’m trying for language that could be easily understood by a “beginner” (as is the concern some here have expressed), while still being fully accurate (as is the concern others have expressed).

Still agreed?
Cheers!
Jerry

Sorry, strike the “assuming phrase”. The #photons hitting the the sensor will vary with ISO at a fixed shutter-aperture combination.