How to easily read a camera's histogram

The camera’s histogram can be intimidating if you don't understand it, but it's actually really simple. In the first of a short series, Harley introduces this powerful tool to facilitate photographers' quests for the perfect exposure.

Music and sound effects under Creative Commons License By Attribution 3.0.

Illusive Photography

Alessandro Valli

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VlatkoBlazek: Mechanical Whirring

leosalom: Fire

[JayGaulard]

This is, by far, the best explanation of the histogram I've seen so far. Nice job!

[emmgeevideo]

I’m an advanced amateur who has learned a lot about my camera (Fujifilm X-T3) but am just learning about the histogram and how to use it to get good exposures. It is a surprisingly elusive concept. I’ve watched a number of YouTube explanations — yours is the best so far. But I’d like to critique it a bit. You jump between some concepts that deserve a better bridge.

You start by saying the histogram reflects brightness levels with black on the left, gray on the right, and “levels of gray” in the middle. This is where the first bridge is required IMHO. I’m looking at a color image in the viewfinder. The histogram is telling me how much black, white, and gray is in the image? What about “brightness levels”? That’s three concepts with no connection (color, B/W/G, and brightness).

I like the Pixel Man and the four levels of white, dark gray, light gray, and white. But again you don’t bridge the concepts. How does the color image map to the four levels of B/W/G? You go on to mention how the histogram shifts during the day? This implies that brightness is involve but how does a green leaf in the tree become dark gray at one time of day and light gray another time of day?

You kind of bridge the concepts when you bring in the two types of histograms: Luminance and RGB channels. But you don’t define luminance. I had to look it up. The first definition I see says, “The intensity of light emitted from a surface per unit area in a given direction.” My interpretation: “The intensity (brightness) of light emitted from a surface and captured by the sensor pixels.” So that tells me that each pixel is recording two things (at least): a color value that is allocated to R, G, or B and a level of brightness (intensity) that is categorized from something (low) to (something) high.

You said that the histogram shows 256 levels but you implied that the value could be lower than 1 and higher than 256 because it is off the chart. These pixels are “clipped” which means anything lower than 1 is assigned 1 and anything higher than 256 is assigned 256. In your other video you mention that you can use the exposure compensation dial to move the histogram in either direction, which implies the camera must be able to translate, say, 300 into a value of 256 or less if you move the exposure compensation dial in the negative direction.

I’m guessing that the RGB channel histograms are also luminosity histograms — they just show the distribution of luminosity on a channel-by-channel basis.

So I guess that for the black and white histogram (FWIW, Fuji doesn’t give it the name “luminosity”), the color information isn’t used and measures of light are expressed as gray units: 1 gray (black), 2 gray, 3 gray, etc. up to 256 gray (white). You hear people talk about 18% gray (you didn’t mention it that I recall). I’ve heard it said that cameras “expose a scene to be 18% gray”. I guess that means if you have a 1 megapixel sensor and you add up the values of all the pixels (assigned a value of 1-256) and divide by 1, 000, 000 that the average is 18%.

That’s how I bridge this. Am I right? It’s not especially intuitive to look at a color image and understand how it becomes a black and white histogram unless you explain how the color pixels wind up being represented as black, white, and gray.

[motorhead]

Thank you, this is the clearest explanation I have watched on histogram.👍

[allanbyrd]

This is the best information I have found on the histogram. I am relatively new to digital, coming from many years back doing film. Once I started paying more attention to histogram, my pic improved. But didn't completely understand what was going on. Thought the bell-shaped curve was best. Your video is a tremendous help. Well done! Many thanks. I will be exploring more of your video. I am interested this application in LR and PS.

Regards,
Allan

[dacwebb]

 I never knew what I was looking at when I viewed the histogram.  This has helped a lot. Thank you. :)

[JohnDoeHZ]

Great job! I've been looking for a video like this for years (on and off). I thought of making one myself, but you did pretty much exactly what I was planning to do... but better. The histogram is such a powerful tool and not even the professionals have succinct explanations like this. I will save this link dearly and share to all my friends who ask "how do I get better photos?" Use the histogram and avoid clipping!

[SJ-gjmx]

Very good explanation of histogram...really this was the best youtube channel for histogram

[ThatJapaneseManYuta]

Thank you! Your explanation was very easy to understand!

[georginap]

short simple but sweet ..Excellent teaching method..why do others make them so complicated...Im now a fan ..Looking forwards to learning more from House of Hacks

[krishnaprasadlama]

very clear explanation on the subject of camera histogram. thanks a lot

[MrKen-wydk]

Great and entertaining tutorial. I'm on to the next one. Subscribed!

[byronkleoyang]

Good job. Great production and information was easy to understand. Thank you for your hard work. Subbed.

[NerologicalAdventure]

Excellent, I have been looking for something like this.

[jeksonps_vi]

I Just know the benefits of RGB histogram what for, It help in correction of white balance as well. Did I understand right?
Thank you for your great tutorial video

[MattJNeale]

Your voice reminds me of Tarantino haha! Good video man, thanks.

[seijikawamura]

How do I find the Histogram in my Sony @A7c ?

[kennynvakehve]

So it's not telling you where in the photo that it is over or under exposed...it is showing the whole photo in general, ..well, to me the histogram should show where in the photo it is over or under exposed...wouldn't that make more since? My idea of a histogram is to show where it needs help, as in your histogram is an exact copy of your photograph except smaller like the size of a histogram today ...it's just a thought. but nice video...I am new to using the histogram myself...I kinda know what it is..and how to use it..but not like I should know.