The Limits of our Histogram and how to Ditch the Rules!
The histogram is one of the most important tools that our cameras and editing software possess.
It gives us an easy to read, visual representation of the distribution of light through our images. It allows us to control our exposures with a great deal of finesse. Fine tuning the way the light behaves on our image and giving us great creative control.
We are often told that we should stay within the limits of our histogram and for the most part, this is good advice.
It means that we are not pushing beyond the boundaries of our sensor’s capabilities. This, in turn, means we will get maximum quality from our image.
Why we Might Go Beyond the Limits
There are times when we might want to push the boundaries of the histogram, to the edge and beyond. This might be to the left of the histogram, underexposing the shadows or to the right, pushing, even blowing the highlights.
Of course, if we push the limits of our sensor we can potentially reduce image quality. We should keep that in mind as a side effect of getting a great shot, but not let it rule the way we shoot.
One thing to note here is that shooting RAW will reduce the impact of pushing the limits. It’s also worth noting that in camera our histograms display the output from JPEG files and not that of RAW.
It is probable that we can push past the outer limits of our histogram slightly without any deterioration of the image.
Seeing the Light by Pushing to the Right
Let’s look at pushing the histogram to the right.
There are a couple of reasons you might want to do this. The first is the known phenomena of “shooting to the right”.
Because of the way sensors work, there is a school of thought that suggests that exposing your image to the right of the histogram gives you a better dynamic range and a more durable image for post production.
This is a useful technique for high contrast subjects as it allows you to gain more shadow detail in post production. If you do not wish to deliberately clip the highlights you need to keep the exposure on or just outside of the right end of the graph.
The other area where pushing the histogram is useful is for high key photography. High key is where the image uses a predominance of lighter tones.
With high key, you can often push beyond the limits of our histogram (to the right side). This can result in the very bright, white out backgrounds often associated with this type of photography.
Going Dark by Pushing to the Left
At the opposite end of the histogram, there are also good reasons for pushing the limits. One of these is to create the so-called cinematic effect.
The technique is called crushing the blacks and can be done in camera or in post production.
The idea is to push the darker parts of the image to become pure black, giving a film like cinematic effect. To achieve it you need good strong shadow areas in the first place. By exposing to the right we remove any light in the shadows giving us that deep contrasty look.
A similar effect to this is low key photography where we use deep shadows to dramatically highlight the lit areas of the image. By exposing for the bright, well-lit areas of say a model's face, we automatically darken the shadow areas.
One area where shooting to the left of the histogram is useful is in landscape photography. It is particularly useful in stormy light with long shadows. By pushing the underexposed shadows, we can use them as a compositional device to highlight the subject in the scene.
Limits of our Histogram – A Summary
Modern sensors are incredibly capable and forgiving pieces of technology.
We should not be afraid to be confined by the histogram all the time.
As mentioned earlier, most cameras base that histogram on a JPEG output. This means you can go beyond the limits to a certain extent without incurring image degradation.
However, if there is a shot in front of you that begs for you to push beyond the limits of your sensor then don’t be afraid to capture it. Some of the greatest images in history have been less than technically perfect.
Further Resources
- 3 Hugely Common Misconceptions About Histograms by Russell Goodman
- How to Give Give Your Shots the Cinematic Look in Lightroom by Jason Row
- Histograms: The Key to Perfect Exposure by Jason Row
- Lighting – High Key and Low Key by Udi Tirosh
Further Learning
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2 Comments
Thank you Mr Row,
For your explanation of using a histogram. One point you made is that it helps you expose clipping, That’s how I use it in my editing process. Most of my images are on the dark side so my histograms are to the left. I turn on the warnings for both right and left and when I see the blue and red masks showing I use my adjustment brush to wipe away the clipped areas. Also I believe that the histogram is valuable for soft proofing. As long as you set your ICC profile accurately to match the media and printer you are using.
Good Tutorial. I will try some of this due to your effort to present the issue.
On another note, I wish you wouldn’t make the images you use so large that they do not fit on a normal page. I use LibreOffice Writer to save these tutorials for later reading, but must make special efforts to reduce all of the photo images so they will fit. What a pain! I’ve already influenced one blog presenter of photography articles to change his behaviour in this regard. I hope this may have the same effect. Thanks for your efforts.