Triangle?

[Iliah Borg]

I've ... erased from your brain any and all information about how much light the sensor needs to produce a high-quality photograph...

You are resorting to utter absurd.

Think of this: how the quality of a photo relates, in terms of noise and artifacts, to the photographic exposure?

 

[J A C S]

Let's do a thought experiment.

Before we move to the next goalposts, how do you answer my question?

So ISO does not affect exposure after all?

 

[SmilerGrogan]

It is not at all absurd. It is a logical consequence. When you say "ISO is not part of exposure" you deprive photographers of the camera manufacturer's guidance on how much light the sensor requires to produce an exposure (see below). The result is that photographers will either have to guess at shutter and aperture or conduct their own exposure tests.

As for "how the quality of a photo relates, in terms of noise and artifacts, to the photographic exposure"? Under your system there's no way of knowing because the "no-ISO" system rejects any notion of quantifying a sensor's sensitivity.

Fortunately the ISO has a very simple explanation for "photographic sensitivity" that is as useful as it is succinct.

"general term used for numerical values calculated based on the exposure at the focal plane of a DSC which produces a specified DSC image signal level, such as the standard output sensitivity or recommended exposure index
Note 1 to entry: In practice, the photographic sensitivity is often called the "sensitivity" or the "camera sensitivity". It is sometimes called the “ISO sensitivity”, for historical reasons that date from ISO standards for photographic film cameras."

I've ... erased from your brain any and all information about how much light the sensor needs to produce a high-quality photograph...

You are resorting to utter absurd.

Think of this: how the quality of a photo relates, in terms of noise and artifacts, to the photographic exposure?

 

[Iliah Borg]

Fortunately the ISO has a very simple explanation for "photographic sensitivity" that is as useful as it is succinct.

"general term used for numerical values calculated based on the exposure at the focal plane of a DSC which produces a specified DSC image signal level, such as the standard output sensitivity or recommended exposure index
Note 1 to entry: In practice, the photographic sensitivity is often called the "sensitivity" or the "camera sensitivity". It is sometimes called the “ISO sensitivity”, for historical reasons that date from ISO standards for photographic film cameras."

Only you don't understand that very simple explanation.

I've asked you above:

how does the quality of a photo relates, in terms of noise and artifacts, to the photographic exposure?

And you still can't bring yourself to give a direct answer.

Instead you again resort to an absurd:

Under your system there's no way of knowing because the "no-ISO" system rejects any notion of quantifying a sensor's sensitivity.

Sensor sensitivity is not rated in ISO photographic sensitivity units. ISO standard doesn't even consider sensor sensitivity. It even excludes raw from the discussion. Given that, how do we get the good exposure for raw? We monitor clipping, or we use workarounds.

1/100 f/5.6 ISO 100 is the same exposure as 1/100 f/5.6 ISO 10,000.

 

[spider-mario]

It is not at all absurd. It is a logical consequence. When you say "ISO is not part of exposure" you deprive photographers of the camera manufacturer's guidance on how much light the sensor requires to produce an exposure (see below). The result is that photographers will either have to guess at shutter and aperture or conduct their own exposure tests.

If they shoot RAW and they want the absolute best quality that their camera allows, then they pretty much already have to do that with current cameras. (And possibly even forgo automatic white balance in favor of “UniWB”.)

As for "how the quality of a photo relates, in terms of noise and artifacts, to the photographic exposure"? Under your system there's no way of knowing because the "no-ISO" system rejects any notion of quantifying a sensor's sensitivity.

So does ISO. If 0.1 lx·s produces a mid-tone in the processed image, then that’s ISO 100 regardless of the proportion of photons that the sensor actually captured.

 

[Chris Noble]

Think of this: how the quality of a photo relates, in terms of noise and artifacts, to the photographic exposure?

It depends on what type of quality you are looking for. Quality is not a number.

 

[spider-mario]

Think of this: how the quality of a photo relates, in terms of noise and artifacts, to the photographic exposure?

It depends on what type of quality you are looking for. Quality is not a number.

SmilerGrogan mentioned “information about how much light the sensor needs to produce a high-quality photograph”, which suggests the existence of a relation between the amount of light and what SmilerGrogan meant by “quality” in that specific comment. Iliah asked SmilerGrogan to think in detail about that relation, “in terms of noise and artifacts”.

 

[Chris Noble]

Think of this: how the quality of a photo relates, in terms of noise and artifacts, to the photographic exposure?

It depends on what type of quality you are looking for. Quality is not a number.

SmilerGrogan mentioned “information about how much light the sensor needs to produce a high-quality photograph”, which suggests the existence of a relation between the amount of light and what SmilerGrogan meant by “quality” in that specific comment. Iliah asked SmilerGrogan to think in detail about that relation, “in terms of noise and artifacts”.

Good! So if there is "enough light" to "produce a high-quality photograph", you shoot at base ISO, and ISO setting does not enter into the equation (sorry, into the triangle).

But if there is not enough light? Now what type of quality are you looking for? And if it's still "in terms of noise and artifacts", how do you minimize those?

 

[Karl Persson]

Think of this: how the quality of a photo relates, in terms of noise and artifacts, to the photographic exposure?

It depends on what type of quality you are looking for. Quality is not a number.

SmilerGrogan mentioned “information about how much light the sensor needs to produce a high-quality photograph”, which suggests the existence of a relation between the amount of light and what SmilerGrogan meant by “quality” in that specific comment. Iliah asked SmilerGrogan to think in detail about that relation, “in terms of noise and artifacts”.

Good! So if there is "enough light" to "produce a high-quality photograph", you shoot at base ISO, and ISO setting does not enter into the equation (sorry, into the triangle).

It never does.

But if there is not enough light? Now what type of quality are you looking for? And if it's still "in terms of noise and artifacts", how do you minimize those?

By changing the exposure.

 

[ThrillaMozilla]

Think of this: how the quality of a photo relates, in terms of noise and artifacts, to the photographic exposure?

It depends on what type of quality you are looking for.

Ooh. I know the answer. How about noise and artifacts? Those are qualities.

Quality is not a number.

No, but noise and artifacts are qualities, and they can be specified by numbers.

 

[spider-mario]

Good! So if there is "enough light" to "produce a high-quality photograph", you shoot at base ISO, and ISO setting does not enter into the equation (sorry, into the triangle).

On many cameras, the setting actually kind of does, by influencing the relative contribution of electronic noise, see below. (The standard appears to now make an explicit difference between the “DSC ISO sensitivity setting” and the effective ISO value of the produced image.)

But if there is not enough light? Now what type of quality are you looking for? And if it's still "in terms of noise and artifacts", how do you minimize those?

Essentially, the general strategy for a RAW shooter is described in section 5.8.3 (“Image quality” -> “Practical strategies” -> “Exposing to the right”) of Physics of Digital Photography , an excerpt of which follows:

 

[J A C S]

Essentially, the general strategy for a RAW shooter is described in section 5.8.3 (“Image quality” -> “Practical strategies” -> “Exposing to the right”) of Physics of Digital Photography , an excerpt of which follows:

This is not ETTR, or for a RAW shooter only. It is the reason ISO exists in the first place and applies even when you shoot in the green square mode.

 

[spider-mario]

Essentially, the general strategy for a RAW shooter is described in section 5.8.3 (“Image quality” -> “Practical strategies” -> “Exposing to the right”) of Physics of Digital Photography , an excerpt of which follows:

This is not ETTR, or for a RAW shooter only.

I am not sure that I understand your point.

It is the reason ISO exists in the first place and applies even when you shoot in the green square mode.

Please correct me if I am wrong but I think you mean that this is why ISO is generally implemented using analog gain, not why it exists. It exists to relate exposure to tone reproduction.

 

[J A C S]

Essentially, the general strategy for a RAW shooter is described in section 5.8.3 (“Image quality” -> “Practical strategies” -> “Exposing to the right”) of Physics of Digital Photography , an excerpt of which follows:

This is not ETTR, or for a RAW shooter only.

I am not sure that I understand your point.

It is the reason ISO exists in the first place and applies even when you shoot in the green square mode.

Please correct me if I am wrong but I think you mean that this is why ISO is generally implemented using analog gain, not why it exists.

It is a matter of terminology. To me, a digital ISO would not be ISO. You can do it post-capture. Yes, I know that sometimes ISO is implemented this way.

It exists to relate exposure to tone reproduction.

"Real ISO" exists to lower noise.

 

[Chris Noble]

Think of this: how the quality of a photo relates, in terms of noise and artifacts, to the photographic exposure?

It depends on what type of quality you are looking for. Quality is not a number.

SmilerGrogan mentioned “information about how much light the sensor needs to produce a high-quality photograph”, which suggests the existence of a relation between the amount of light and what SmilerGrogan meant by “quality” in that specific comment. Iliah asked SmilerGrogan to think in detail about that relation, “in terms of noise and artifacts”.

Good! So if there is "enough light" to "produce a high-quality photograph", you shoot at base ISO, and ISO setting does not enter into the equation (sorry, into the triangle).

It never does.

But if there is not enough light? Now what type of quality are you looking for? And if it's still "in terms of noise and artifacts", how do you minimize those?

By changing the exposure.

Ahh, except sometimes your lens is not bright enough, or you can't increase the exposure enough... What then?