Digital cameras from simple point-and-shoot cameras to professional DSLRs comes with an option to display histogram on the LCD screen. Ever wondered what this graph indicates and how can it be useful in photography? If your answer is yes then go on. You can get your photography skills improved.
A histogram of an image is a graphical representation of the number of pixels in an image having a particular intensity value. This type of histogram specifically known as Intensity Histogram is the most common type. Colour histograms (RGB) are also popular but right now lets learn about intensity histograms.
The horizontal axis in the intensity histogram represents the various intensity values. The left end denotes maximum darkness and the right end denotes maximum brightness. All values in between shows different shades ranging from black to white. The vertical axis represents the number of pixels. The higher the graph, the more number of pixels.
So, now we can predict that for a dark image, the histogram will contain a number of tall lines towards the left end and a few short lines towards the right end. Similarly for a bright image, there will be a number of tall lines towards the right end and a few short lines towards the left end.
Now lets see how this can be useful in taking better pictures. The key to a good photograph is proper exposure. The image should be neither too bright nor too dark. It should be evenly exposed. That is the number of dark pixels and number of bright pixels should be minimum. Here dark means black and bright means white. So how would a histogram of a perfect image look like? The histogram would have the shape of a hump with the maximum at the center of the graph and gradually decreasing towards both ends. Now take out your camera, switch on the histogram display and walk around. Take different shots and see the relation between the lighting, quality of picture and the histogram. Practice with it and you will be soon able to handle it involuntarily.
Warning: Use the histogram only as a guide to take photographs and don't depend on it completely. Some photos might look good for your eyes but bad on the histogram. So always go with your eyes and basic judgment.
A histogram of an image is a graphical representation of the number of pixels in an image having a particular intensity value. This type of histogram specifically known as Intensity Histogram is the most common type. Colour histograms (RGB) are also popular but right now lets learn about intensity histograms.
The horizontal axis in the intensity histogram represents the various intensity values. The left end denotes maximum darkness and the right end denotes maximum brightness. All values in between shows different shades ranging from black to white. The vertical axis represents the number of pixels. The higher the graph, the more number of pixels.
So, now we can predict that for a dark image, the histogram will contain a number of tall lines towards the left end and a few short lines towards the right end. Similarly for a bright image, there will be a number of tall lines towards the right end and a few short lines towards the left end.
Now lets see how this can be useful in taking better pictures. The key to a good photograph is proper exposure. The image should be neither too bright nor too dark. It should be evenly exposed. That is the number of dark pixels and number of bright pixels should be minimum. Here dark means black and bright means white. So how would a histogram of a perfect image look like? The histogram would have the shape of a hump with the maximum at the center of the graph and gradually decreasing towards both ends. Now take out your camera, switch on the histogram display and walk around. Take different shots and see the relation between the lighting, quality of picture and the histogram. Practice with it and you will be soon able to handle it involuntarily.
Warning: Use the histogram only as a guide to take photographs and don't depend on it completely. Some photos might look good for your eyes but bad on the histogram. So always go with your eyes and basic judgment.
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