 Posted 4/7/2007 7:22:55 PM
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| I know I have asked about it before but you know these things go in stages and I know there are others out there who need this too sooo. I remember Richards example of a good histogram but I need more info ..such as....How does one read one exactly?...now in PS I have the histo tool which ( I believe it is the same on the camera and all other software I would imagine) has the RGB and the color..Do I have to keep looking back and forth at both of these or will the RBG give me the primary indication of what is good?..I also really dont know how to read the wave... if it is higher in the middle than on both ends this is the goal?...or as long as the colors are all on the same "wavelength" as the RGB it is good or are all the colors also included in the RGB graph?... Hey thanks...I suppose everyone is busy and I will be tomorrow so take your time..appreciate it.
I may not always be wRIGHTbut I am never wrong Profile -  Top 24 - 
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Posted 4/7/2007 8:44:22 PM
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Eye Pleasing Exposures
Use the histogram to check your exposure of the scene. Avoid large accumulations of pixels at 0 and 255. When you have big stacks of pixels at the extremes, it means you have lost detail in the shadows and/or the highlights. This directly correlates to overexposure and/or underexposure.
Trust the histogram. It will deliver you to the promised land.
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Posted 4/7/2007 9:12:19 PM
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Posted 4/8/2007 6:42:45 AM
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Tonka (4/7/2007)
I know I have asked about it before but you know these things go in stages and I know there are others out there who need this too sooo.
I remember Richards example of a good histogram but I need more info ..such as....How does one read one exactly?
I had it explained this way once...
Open a picture and zoom WAYYYY in. Eventually you will start to see the pixels as squares. Now, imagine these squares are all tiles. So you have this tile mosaic that when you "stand" far enough away looks like a photo.
Okay, now imagine that all these tiles fall off the wall. (maybe from an earthquake or something). Now you have this mess of all these tiles and you want to put them back and reconstruct the picture. Well, it would be crazy to just start putting tiles back on the wall without organizing them. So, you decide to sort them by color. So, you take all the black tiles and stack them in one tall stack. This is stack 0. (0 zero because 0 = black in a 8 bit image), Then on the right side of black, you stack all the tiles that are one step lighter than black and this is stack 1. You keep making stacks that are lighter and lighter until you get all the way to pure white (stack 255 to the far right). Now, step back and take a look at this line of stacks of colors that run from left to right. There you have a histogram.
The color histogram is basically showing you the same thing only, letting you look at colors in the red, blue and green groups individually. I am not certain of the point of that and I never use it. Then you can also look at the channels individually, which is basically the same as above only you are looking at one channel at a time.
As far as histograms being the same in the camera as in Photoshop, they should be pretty close to exactly the same thing, unless you are using a different color space. In my camera, I can choose what color space to shoot in, just as I can choose in which to work in Photoshop.
So, reading the histogram in the camera is telling you what the balance of each luminosity value. If you look at one that is smashed to one side or the other (usually with a large spike at the very end) that indicates an improper exposure. It means some of your shadows or highlight information is not available inside that image. The camera "clipped" them.
Allllrighty then!
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Posted 4/11/2007 9:07:05 AM
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En , thank you for that very good visual  ....I am wondering though if the colors should be even? or if it is proper to try and have them gradually peak in the middle... I also have to read my manual,,,I will do that right now...I know where that option is but not how to have it on my display... Will get to that...I did not know that these directly related to exposure and that many ill exposed images of mine could have simply been avoided...it may have not sunk in ,,this point...... Many times when I have a histogram that looks close to Richard's example,, I think it looks horrible?..for my pic that is... I do view the histograms but usually after they have been uploaded and I am processing them..so I need to read right now...... thank you so much for your help....Everyone !
I may not always be wRIGHTbut I am never wrong Profile - Top 24 -
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Posted 4/11/2007 5:48:04 PM
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| Okay..i did some reading today...I have found my histogram display.... I thought I could have that on WHILST I shot but I guess I was wrong..ya gotta take the pic first , read it and then reshoot if it was not good...bummer. but it is nice to know....geeesh how do you all remember so many things just to take one pic..oye Oh and what does it mean when you have high peaks in between 0 and 255 or is this not important to the point that the extremes are? And again I say,,,when the histogram seems to be okay....I don't like the way it looks..why is this? or does that just mean that though I avoided the extremes, I still not get proper light?
I may not always be wRIGHTbut I am never wrong Profile - Top 24 -
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Posted 4/11/2007 6:21:07 PM
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I found a pretty good illustrated explanation of histograms here.
http://www.luminous-landscape.com/tutorials/understanding-series/understanding-histograms.shtml
As you will see. There is no such things as a good or bad histogram. They are just there as a tool to show you the luminance values of your image, so that you can get a good idea if your image will have any loss of detail in either end of the range (dark colors or light colors). You can also see the number of mid tones, etc.
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Posted 4/11/2007 7:42:06 PM
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| Okay...Cool another good article..man I am runnin out of room here lol.... That was very easy reading too and with lots of visuals..I understood it and got it now.... Thanks En....and you say you are a beginner????
I may not always be wRIGHTbut I am never wrong Profile - Top 24 -
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Posted 4/11/2007 9:28:54 PM
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