it was just a good article about luminance. and does contradict many members writings here.
June 16, 2023
577
-
-
But you need to understand it.
As I said, you misunderstood the article.
Feel free to ask questions. -
Which article?
Which histogram?
What is exposure level? -
Not sure what you're talking about. Be explicit about the contradictions that you see. List them.
-
This one? (not a trap)
-
-
no but it says the same as this one.
-
I don't find "Exposure levels" there.
-
Word for word, interesting, thanks.
-
keep reading
-
I like the wording.
Identical exposure settings shutter+apeture+iso
-
what does these histogram tell you about the exposure
Notice how the patches show differently in the 2 histogram even when they represent the same lab values.
How those values are shown in a histogram vary depending on what that distribution of data represents in a color space.
(both are of jpg images and not raw) -
So what? I don't see the point you are trying to make.
When using flash you have 2 exposures* to deal with - the ambient exposure* and the flash exposure*
The flash exposure* can be set automatically by the camera using ETTL or manually.
Even though the aperture, shutter speed and ISO are the same in both shots the total exposure* for Screenshot(5) was larger because more light from the scene hit the sensor due to the additional light added to the scene by the flash.
The 2 luminosity histograms are about what I would have expected for those shots.
* exposure - amount of light that struck the sensor per unit area while the shutter was open
-
Both articles are misleading. Capturetheatlas more because he determines the exposure using LR histogram, not the RAW one.
Artschoolportals article is better but I don't like the way they use PS Levels as example of exposure. -
They are not here is a hint for part of the scene you introduced more light thus altering the exposure
-
The exif for the shots shows the aperture, shutter speed and ISO are identical for both shots but the exposure* is not the same as described earlier.
* exposure - amount of light that struck the sensor per unit area while the shutter was open
-
You are misunderstanding what is explained in those articles.
Consider this image with pure red (255,0,0), green (0,255,0) and blue (0,0,255) pixels on a pure white (255,255,255) background.
This is the RGB histogram for the image.
This is the luminosity histogram for the same image.
A histogram of any kind - RGB, Luminosity, whatever - is just a frequency count of some values - RGB, luminosity, the number of various coloured cars crossing an intersection etc etc etc - and nothing more.
-
im not disputing that. have you a better way to show scene luminance ?
