Histogram is quick way to analyze exposure in photography. It helps us to understand how much details each image has preserved. Pixel details should not loose because of dark shadows or due to too much highlight in photograph. In this article we will be Understanding Histograms Statistics and How to Read A Histogram in Lightroom with example. 

What is Histogram :

Now a days histogram can be found in almost every camera and image editing software. Some camera allows a live view as well if you shoot through LCD. Histogram has become very important and helpful to understand in how much details each part of image carries. Many photographers do find it difficult to read in start, I agree it looks very complicated with up n down vertical bars but believe me its very easy to understand and quite helpful too. Here in this blog we will try Understanding Histograms Statistics in Photography. 

A histogram is a graphical representation of the tonal values of your image. In other words, it shows the amount of tones of particular brightness found in your photograph ranging from black (0% brightness) to white (100% brightness). The middle portion of the histogram represents mid-tones, which are neither dark nor light. Vertical axis of a histogram displays the amount of tones of that particular lightness. 

Understanding Histograms Statistics :

The left side of the graph represents the blacks or shadows, the right side represents the highlights or bright areas and the middle section is mid-tones. How high the peaks reach represent the number of pixels in that particular tone. Each tone from 0-255 (o being black and 255 being white) is one pixel wide on the graph, so imagine the histogram as a bar graph all squished together with no spaces between each bar.

Gaps on either end indicates you are missing information and your exposure can be shifted safely without losing detail.

You also have to remember, if there is a sun in your image then obviously it would be very bright and white and in this part of the image due to this highlight you could loose some details around this portion of image.

Histogram and Exposure : How to Read A Histogram in Lightroom

Underexposure:

This is a underexposed image (very dark) where you can hardly see any details. If you check here (top right side) in histogram, it clearly shows a strong shift to left side which means most of image is in shadows and completely black.

Overexposed:

This is a overexposed image (too much light) where many tones are very bright with almost no dark tones in pictures. Due to too much light almost entire image is blown-out and lacks details. Check histogram here, it clearly shows a strong shift to right side, which means most of image is too bright and blown-out (completely white and bright). 

Correct Exposure:

Lets analyze histogram here, there is no vertical bars on either side of histogram, which means there is no detail lost in shadows or there is no part of image which has been blown out because of too much brightness. If you see closely, histogram spikes up on the portion of image where parrot is placed. This part of histogram showing the tones of parrot, it is properly exposed and has enough details too.

Breaking the Rule :

What about this image? Is it underexposed ? very dark with no details.. Right ? Here Histogram also tells us that super strong shift to the left side which means image is in shadow and lack details.

Would you try to correct it ? Off course NO. The truth is histogram can not be evaluated on the basis of exposure. The correct histogram depends on many factors. Histogram merely shows you the amount of tones of various brightness levels in your image, and nothing more. It can be used to discover whether you have chopped any highlight or shadow detail at specific exposure settings. 

Conclusion :

Many photographers makes a good habit  of seeing histogram after click just to make sure nothing on the extreme right or left. Well, this habit is not going to make you a good photographer and you should also have enough time to look through LCD and analyze histogram. However, you should know how to read histogram which is helpful and invaluable in some situation at times.

Hopefully, this article helped you to understand what histograms is all about and how to read it.

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