In today’s article, we want to talk about how to read a histogram for photography and videography.
What is a histogram?
It’s basically a graph that visually represents the exposure of each pixel in your image. On the left side of the graph, the blacks and shadows are represented. On the right side, the highlights and brighter areas are represented. The middle section includes mid-tones. The higher the peak in each section means the more pixels at that exposure.
The graph goes from 0-255 (0 being black and 255 being white). And each tone is one pixel wide on the graph. Check out the visualization below. You can see that there are lots of brights in this image (without even seeing what the image is!).
How can we use the histogram?
First, we can tell if the image is well-exposed. If the graph has pixels going from 0 to 255 (from black to white) without any crazy spikes, then you have a well-exposed image.
The first image to the left is a good example of this. The second image will be over-exposed (too bright), and the third image will be under-exposed (too dark).
In the second image, the blank space on the left side of the histogram tells us that we need to change the exposure using our cameras control options such as aperture, shutter speed, or ISO. Watch this video here to learn exactly how to fix exposure.
Beware of the spikes!
Spikes on the right or left side of the histogram mean that the data captured at that exposure will be unrecoverable. So when editing these photographs, you won’t be able to darken or brighten these areas of the photo. It’s okay if the histogram touches the sides, just not spikes up at the sides.
Remember when you can throw out the rules!
As always, remember when you should throw out these rules. Some pictures that you want to take will have completely underexposed parts of the frame that will result in a spike. For example, night photography – pictures of the sky will often have pure blacks. Sunsets will sometimes have pure whites (coming from where the sun is). Just because you know what the histogram is telling you to do, doesn’t mean you should follow it.
The histogram is yet another tool. You’re the artist.
Thanks for checking out VideoSchoolOnline.com, I really appreciate it. If you have any comments or thoughts about photography, let us know in the comments below!