Demystifying Histograms

480sparky · Dec 30, 2012

BlackSheep said:
Excellent post, thank you for taking the time to do it Sparky.

I was bored to tears last week when the big snowstorm rolled in. Just polished it off this morning.

BlackSheep · Dec 30, 2012

Your boredom was well directed.
Not just for total newbie photographers, but also for us former film shooters who are still struggling with the whole histogram concept. Much appreciated!

nmoody · Dec 30, 2012

Bookmarked this for later, it looks very detailed and easy to understand.

Thanks for taking the time to break this down and explain it.

weepete · Dec 30, 2012

Well done Sparky, very well explained thank you, it is much appreciated mate!

Farmclicker · Dec 31, 2012

I appreciate it as well. Thank you very much for all the time that went into that. I know a lot more now (Which is not hard because I know very little).

Buckster · Dec 31, 2012

Well explained Sparky. That will be a really huge help to those who are unfamiliar with histograms. Good job!

ratssass · Dec 31, 2012

...another door opened for me,and now it has also spilled over into PP.Thanks Sparky!!

jwbryson1 · Dec 31, 2012

Great job as always Sparkomatic.

I do have remaining questions that I will continue to explore on my own, but I'd love to hear more about them here if anybody is up to the task:

1. In LR3 and LR4, I'm not sure that there is a function where you can "slide the triangles" to get the contrast adjusted without banding. Does anybody know if this exists and where to find it in LR3 or LR4?

2. Do all three colors in the RGB histogram have to stretch out across the spectrum from left to right to be a "correct" exposure?

3. Does it make a difference in terms of a "correct exposure" which colors in the histogram appear the highest on the histogram? (I think this may be a "duh!" question and the answer involves what colors appear in the image, but I'm throwing it out there just to see if it sticks).

Thanks!

480sparky · Dec 31, 2012

jwbryson1 said:
...........1. In LR3 and LR4, I'm not sure that there is a function where you can "slide the triangles" to get the contrast adjusted without banding. Does anybody know if this exists and where to find it in LR3 or LR4?

I'm not a LR user, but I'd say you have a lot more latitude when adjusting the white & black points ("slide the triangles") when you are working with a raw file as opposed to a JPEG.

jwbryson1 said:
2. Do all three colors in the RGB histogram have to stretch out across the spectrum from left to right to be a "correct" exposure?

Not necessarily. If you take a photo of a yellow flower, the blue portion of the histo may show an 'incorrect' exposure, but since there's not much blue in the image to begin with, you can ignore it.

jwbryson1 said:
3. Does it make a difference in terms of a "correct exposure" which colors in the histogram appear the highest on the histogram? (I think this may be a "duh!" question and the answer involves what colors appear in the image, but I'm throwing it out there just to see if it sticks).

The 'height' of the histogram is really not relevant unless it's at one end or the other. That would indicate an over- or under-exposure.

Mully · Dec 31, 2012

In LR the histogram is displayed in RGB in PS levels the histogram is a combination of all colors and effects the overall light and dark of the image. Exposure is "most often" correct when the histogram is close L to R ...in a dark or light scene this will change with most of the info L for dark or R for light images. I use PS to change levels and not in LR

CherylL · Dec 31, 2012

Thanks for taking the time to post this tutorial.

ronlane · Dec 31, 2012

Way to go Sparky. Thanks for putting this together. I read and understand what you are showing us. Now I just need to get home and play with it on the camera and in post.

jwbryson1 · Dec 31, 2012

Mully said:
In LR the histogram is displayed in RGB in PS levels the histogram is a combination of all colors and effects the overall light and dark of the image.

???? :scratch:

Rick58 · Dec 31, 2012

Hey Sparky...THANK YOU!

Before even reading this I want to thank you. I'm dumber then a sack of hammers when it comes to histograms. Time to pour a cup of coffee and read through this when I get home. Looks very interesting and thanks for the effort :hail: