Understanding Histograms in Photography


Histograms – How to use it for Photography

Histograms are useful tools to determine how well an image is exposed.  Most modern-day digital cameras have some histogram to display if your image is correctly presented.  DSLR’s mainly show a live histogram so you can adjust your settings while composing a shot.  Others will only show a histogram when previewing an image.  It can be a little tricky trying to understand them at first, but once you know how it works, it is pretty easy to use them to shoot your image depending on what field of photography you are in.

Understanding the Histogram

There are five separate groups defined in the histogram.  They will not be broken up for you when you see it, so you have to visualise where they are broken up.

  1. Blacks
  2. Shadows
  3. Midtones
  4. Highlights
  5. Whites

The key to getting a good exposure is keep everything near the mid-tones as best as possible.  More importantly, any information that is more to the left (blacks) or the right (whites) will risk a loss of exposure or information.  This becomes more noticeable when editing or viewing on a larger screen rather than the camera screen.

An example of a histogram. A useful method is to get the exposure mostly in the middle of the histogram unless you intentionally want to underexpose or overexpose. Too much information on the far left or right risks loss of exposure which may be unrecoverable.

The histogram is taken from the below image.  While it falls more towards the blacks and shadows, the mid tones are right to give this image a proper exposure.

Image used for the histogram above. It shows no overexposure or no excessive blacks.

Over Exposure & Under Exposure

As an example, I will use Photoshop to overexpose & underexpose the image above to show how the histogram moves.

Example of overexposure. If this was taken through a camera, then most of the information on the right would be lost. The highlight clipping warning light has also changed from black to blue. It can be worked on through editing, but the finish would not look like how it usually would if exposed properly in the first place.
Example of an underexposed image. The shadows are too dark for the exposure. The shadow clipping warning has also changed colour. Again as above, some work would be needed to recover this, and it may not look right.

Does it Work Every Time?

Using this tool can help to get your exposure right.  But it is not necessarily true when shooting particular scenes.  When shooting high key images, you want the information to expose to the right more.  The same can be said for underexposing.  For example, a night scene will have lots of darks due to the sky.  When underexposing or overexposing is intentional then leave it as it is.

Final Words

This is just a short explanation of using histograms.  They are useful things to use but should not be relied on all the time as it depends on the scene or situation you plan to shoot.  It can help to improve your photography by understanding exposures for your subject.

1 Comment

  1. Bablofil
    19th April 2017

    Thanks, great article.


Leave a Reply

Your email address will not be published. Required fields are marked *

Scroll to top