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@ggbutcher has written:I've taught a lot of computer science, and in that body of teaching there are a lot of posited analogies. Some work better than others, a lot of them just serve to confuse even further. And, the success in using any particular one really depends on the specific audience...
My suggestion is to discard all this "geometry" and just concentrate on understanding the mechanism itself...
As someone who taught a lot of math courses, geometry included, never discard geometry.
Oh, can't throw it away, I wouldn't know how to cross-cut my lawn... I just cringe at its application to qualitative discourse.
Disclaimer: 3 university degrees, four math courses among all of them. It can be done... 😝
@JACS has written: @ggbutcher has written:I've taught a lot of computer science, and in that body of teaching there are a lot of posited analogies. Some work better than others, a lot of them just serve to confuse even further. And, the success in using any particular one really depends on the specific audience...
My suggestion is to discard all this "geometry" and just concentrate on understanding the mechanism itself...
As someone who taught a lot of math courses, geometry included, never discard geometry.
Oh, can't throw it away, I wouldn't know how to cross-cut my lawn... I just cringe at its application to qualitative discourse.
Disclaimer: 3 university degrees, four math courses among all of them. It can be done... 😝
The said Triangle, apart from controversy, is no good to me because I always use base ISO. Therefore, taking away ISO as a variable leaves me geometrically with a line ... just as adding EC above apparently begets a quadrangle.
Have I just proved the falsity of using the sides of geometric figures to demonstrate stuff? ...
... come back nomograms - all is forgiven
ISO which regulates sensitivity to the light
As a matter of fact, ISO doesn't do that. ISO is a lame film analogy. Also, ET suggests ISO regulates noise.
@yawlenz has written:If an in-camera push development of a raw file is not equivalent to an increase of ISO, except for resultant image brightness, then what is the exact difference between the two manoeuvres?
Sensors clip hard. Changing the mis-named "Exposure" control in Lr introduces a shoulder, kinda like film. In some cases, increasing ISO can result in a decrease in read noise, especially in dual conversion gain cameras. Did you read the Lensrentals blog posts that I linked to above?
@yawlenz has written:Are there any clear limits to this IQ retention when the pushing is done in-camera?
Clipping.
Much as I'm coming to believe expert advice that a dedicated pp suite would offer way finer controls by a more specialized toolset, does your answer imply that in-camera push processing will not or could not possibly introduce a shouldering to the highlights' section? Or would what there is to that just be wholly insufficient? Before I must have thought that this is a function usually performed by the native tonecurve belonging to a development profile designed by the camera manufacturer, aka a "film"simulation. I'm asking this because I still assume that the physical (fwc) limits on sensor photodiodes will be out of the loop during postprocessing in this meagre way.
Much as I'm coming to believe expert advice that a dedicated pp suite would offer way finer controls by a more specialized toolset, does your answer imply that in-camera push processing will not or could not possibly introduce a shouldering to the highlights' section?
I've never seen that in raw files from Sony, Leica, Hasselblad, Fujifilm, and Nikon cameras. It's possible, but then you could hardly call the files raw.
@DonaldB has written:of cause it does in a very efficent visual sense. just imagine the 4 or 5 of you still cant come up with a better visual concept.
A visual concept might be useful to primary school kids but I don't need a triangle or any other visual concept to understand that for a constant image lightness, not constant exposure*, there is an inverse relationship between any 2 of aperture, shutter speed and ISO.
The misconception the exposure triangle teaches is that for a given scene lighting
f/8, 1/200, ISO 400
and
f/8, 1/100s, ISO 200
are the same exposure* when they are clearly not.
They will both output the same image lightness but the ISO 200 shot has only half the exposure* of the ISO 100 shot and so the ISO 200 shot will have more visible noise because of the lower SNR due to the smaller exposure*
* exposure - amount of light that struck the sensor per unit area while the shutter was open
But Danno, didn't you know that the ISO setting magically changes the sensor's sensitivity - thereby circumventing all known laws of physics?
Before I must have thought that this is a function usually performed by the native tonecurve belonging to a development profile designed by the camera manufacturer, aka a "film"simulation. I'm asking this because I still assume that the physical (fwc) limits on sensor photodiodes will be out of the loop during postprocessing in this meagre way.
It occurs when using all the Lr profiles. There are tone curves baked into those profiles, but what I'm talking about is the way the Lr "Exposure" control works on the data after it comes out of the profile.
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@xpatUSA has written:The said Triangle, apart from controversy, is no good to me because I always use base ISO. Therefore, taking away ISO as a variable leaves me geometrically with a line ... just as adding EC above apparently begets a quadrangle.
Have I just proved the falsity of using the sides of geometric figures to demonstrate stuff? ...
No. The exposure triangle can be thought of as a horizontal slice of an exposure pyramid™. Each horizontal level fixes the lightness. When you fix the ISO, you allow variable lightness levels, thus you stay on one lateral side of the pyramid, instead of on a horizontal slice; and that side is ... a triangle as well. 😲
Interesting! I had never heard of the Pyramid, so I went here:
exposureworks.co.uk/exposure-triangle-aperture-shutter-speed-iso-cheat-card/
The addition of light made it most illuminating. 😉
There, I learned that, if you up the aperture by 3 steps, you should raise the shutter speed by the same ...
.. here in Texas we say "If yew had'na told me that, ah would never of known". Some shorten that down to "Izzadda fak?"
Also learned that, if you up the aperture by 3 steps, you should up the ISO by the same while the shutter speed stays the same by magic.
Quoted message:The 'threeness' of a relationship between three variables is not in question, what's in question is whether the 'exposure triangle' itself offers any additional insight into that relationship, apart from there being three variables.
As I explained, it does.
That depends on which of the several versions you choose.
@DannoLeftForums has written:A visual concept might be useful to primary school kids but I don't need a triangle or any other visual concept to understand that for a constant image lightness, not constant exposure*, there is an inverse relationship between any 2 of aperture, shutter speed and ISO.
Inverse or not, depends on the way you express it but what you are saying is that there is a relationship between the three. Next thing you will be talking about triangles…
Nope, in your actual quote of what I said I explain why I don't need a triangle or any other shape to enable me to understand that for a constant image lightness, not constant exposure*, there is an inverse relationship between any 2 of aperture, shutter speed and ISO 🙂
* exposure - amount of light that struck the sensor per unit area while the shutter was open
@JACS has written: @DannoLeftForums has written:A visual concept might be useful to primary school kids but I don't need a triangle or any other visual concept to understand that for a constant image lightness, not constant exposure*, there is an inverse relationship between any 2 of aperture, shutter speed and ISO.
Inverse or not, depends on the way you express it but what you are saying is that there is a relationship between the three. Next thing you will be talking about triangles…
Nope, in your actual quote of what I said I explain why I don't need a triangle or any other shape to enable me to understand that for a constant image lightness, not constant exposure, there is an inverse relationship between any 2 of aperture, shutter speed and ISO 🙂
It occurs to me that there might some sort of support for that in the ISO Standard Output Sensitivity Method because it is based on a constant image lightness of 118/255.
The cognoscenti of this site should know more about that ...
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@Sagittarius has written:ISO which regulates sensitivity to the light
As a matter of fact, ISO doesn't do that. ISO is a lame film analogy. Also, ET suggests ISO regulates noise.
I call it as it's being called in camera manual, in the books etc. You can call it what ever you feel. And changing it in camera produces the same affect as changing sensitivity to the light (will require more or less light to produce the same image lightness for the same illumination). You can change it in camera or in post, still the same.
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