If you are unconcerned with accuracy, it's easy to come up with simple answers. The truth is that the way it works depends on the camera. I have a GFX 50S. I have a GFX 100S. The ISO settings work differently. Therefore I set the ISO on the two cameras differently.
April 10, 2023
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No, that is not even close to an accurate answer for all situations to the question "...what does the iso dial actually do?"
A much more accurate answer is Michael Fryd's post in the ISO For Beginners thread.
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Sorry, but unless you don’t take the Planck constant into account this is all just wishy-washy talk and doesn’t really explain what exposure is and how the ISO dial works.
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It appears you are the one that is confused because if you raise ISO and leave aperture and shutter speed the same, as you suggest, then the exposure* will not change which is clearly not the scenario I was talking about if you read my posts.
In my posts I was talking about the resultant lower exposure*, and not a constant exposure*, if ISO was raised; a big difference.
* 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. -
"a complete digital still camera." outputting a JPG.
Don
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The photographic triangle is simply a mistake in maths. Three independent variables don't make a triangle, they make a three-axis cube.
Don
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😕😕😕 ???? Not sure who you are replying to or what you are saying ???? 😕😕😕
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They might not be independent depending on the goal. If you want to maintain a constant image lightness, not constant exposure*, then there is an inverse relationship between any two of them.
* 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. -
Danno,
I agree. After way too many arguments with Bob, I agree that ISO is not part of the exposure.BUT… How should the photographer apply this knowledge when shooting?
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I'm sure Bob and others would have answered that question during your 'arguments'.
Unfortunately your question is not related to my original post because I do not use the exposure triangle, and in any case is way to broad a question because the answer depends on what you are photographing at the time and what your aim for the shot is.
Perhaps start your own thread in Beginners Questions with your question and I and I am sure others will be happy to help.
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Jim
Can you expand on that a bit. How can you determine that the ISO settings work differently? What are the consequences for your setting it? Thanks
Sherm -
I believe that a Google search on the subject will help you more than any explanations we can give you.
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A google search for what?
I wasn't asking a question in my original post.
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If it's a debate on what beginners should be told, please start it in Beginners' Questions Discussion. Leave BQ for answering beginners' questions.
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Why should he do a google search? His post is accurate and corrects a very common misconception.
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Is it possible to have too many arguments with me?
Mainly by understanding that if the photographer sets ISO first they are choosing the exposure the'll be using in advance, and it's usually a guess as to what the best exposure would be. Best to set exposure first, then ISO.
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A Google search on the subject will turn up a majority of sources that are simply wrong. I know, I've done it.
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And in any case, there are only two independent variables in play. There is another, but it doesn't find its way into the 'triangle'.
