What is a histogram and why is it important?

Many years ago, only professional cameras came with a histogram. In fact, when I got my Nikon CoolPix 990 back in 2000, it came with one, and I didn't have a clue what it was used for and hence neglected it for a few years. What I should have done was hit the internet and find out about it. Once I figured it out, it has become a very close friend indeed.

Lucky for us today, a histogram is no longer a tool for the professionals. In fact, most cheap digital cameras will give you the option of viewing a live histogram during picture taking on your LCD or EVF. If you’re not using it, you’re missing out big time.

Now what exactly is a histogram?

From this LINK , you will note that it comes from statistics.

However, we don't need to compute anything when we use a histogram in digital photography.

A histogram is nothing more then a representation of brightness in your photograph. It can tell you if your photo will be too dark or too light. Hence, it gives you a visual representation of exposure and scene lighting. DSLRs usually give you the histogram after the shot. You can decide if the photograph you took is a keeper just by looking at it. Compacts however, can give you a far better live version that runs constantly as you are using the camera. You can quickly see if the shot you’re going to take will be properly exposed or not.

Histograms are wonderful tools.

The following links will give you a better more in-depth explanation, and more importantly, visual examples.

Understanding histograms

and

Histogram Explained

and

More about histograms

Now that we know what a histogram is, where else can we use this tool? All digital editing programs have a neat feature called "Levels". It works exactly the same way as a histogram because they are one and the same. The neat thing about levels however, is that you can edit your black, white and midtone points of your photograph.

Here are a few links that will explain this in greater detail.

Levels Tutorial

and

Understanding Curves and levels

and

Fixing an Image with Levels