Exposure understanding and definition

[riveredger]

Useful definition of exposure is the one that is acceptably universal and helps achieving better quality.

What does this sentence actually mean? "...helps achieving better quality "?

It means that a useful definition of exposure helps to predict various technical quality aspects of the outcome of the exposure, instead of implying "high ISO noise" nonsense.

Glad you had no other questions.

 

[Xasan]

I think the point is, you don't understand this topic.

Simple question. Which produces the shot with the least noise, in the same light?

1. ISO 200, 1/60th, f4
2. ISO 800, 1/60th, f4

Do you? Your question is rubbish.

I'm intrigued. How can a question be rubbish? An assertion of fact - that I can see being rubbish. But his question contains no overt assertion.

(And yes, I think Lee Jay does understand this topic pretty well. Do you? Answer the question so we can see.)

The question is rubbish because no terms of reference are supplied.

Hmm, I would have thought all necessary terms of reference are implied by context. Because of that, I'm just guessing at what terms you think are necessary but missing. Let me suggest:

Two shots of the same scene in the same light using the same digital stills camera, a camera that employs variable analog signal amplification as part of its implementation of ISO increase in the indicated range. The light in the scene is not so bright that every pixel is blown at ISO 200, 1/60th, f/4. "Shot with the least noise" means image with the highest SNR calculated from RAW data values before any optional noise reduction algorithm is applied.

I'm just guessing at those being the sorts of terms of reference that you think are required. Lee's response to you indicates a different guess. We have to guess because it isn't at all obvious to us why you don't see these things as implied by the context of the question.

Now either answer the question with these and Lee's explicit terms of reference taken on board, or tell us what other specific terms of reference you think are required. If you don't, people might think you are ducking the question.

I wonder what is it that you are trying to achieve. Obviously you can't explain anything to this 24IS guy. Are you just having fun?

 

[Sara Valentine]

I think this understanding of ISO as one of the three values affecting exposure, while not strictly correct, is deeply embedded in minds of generations of photographers. Should the photographic community try to change it?

Yes

Why

Proper photographic thinking

and how?

Start with the camera manufacturers and implementation of proper terminology

It is almost like reminding people that the Earth revolves around the Sun, so they should not say that the Sun is rising or setting...

Reminding? More like convincing....

 

[Richard B99]

I apologize for bringing this topic again.

I am reading the today's DPR interview with Elliot Shih, Senior Product Manager of Zeiss, about the upcoming ZX1 android-based camera. When talking about the absence of Exposure Compensation dial, the Zeiss manager explained: "If a photographer is manually controlling shutter speed and aperture, then the only way they have of further affecting exposure is ISO. So they can use the ISO dial as exposure compensation, effectively."

I think this understanding of ISO as one of the three values affecting exposure, while not strictly correct, is deeply embedded in minds of generations of photographers. Should the photographic community try to change it? Why and how?

It is almost like reminding people that the Earth revolves around the Sun, so they should not say that the Sun is rising or setting...

Apart from the misunderstanding of ISO, does Mr Shih’s explanation imply that the ZX1 only operate in Manual mode? If not and it has the normal semi auto modes, then it sounds like he was trying to obfuscate the need for an EC adjustment that alters the way the camera sets the other (third parameter) itself. In manual you don’t need EC because the meter is purely advisory and you can take a pic at any ‘brightness’ level.

I strongly suspect the root cause of the exposure thing is the cameras meter indicator that is usually called Exposure. That uses all three parameters inc ISO to determine the target ‘exposure’ mid-point on the scale. I think this has so much to do with the general confusion here. That’s been going on for decades since such meters appeared in cameras.