Getting your exposure correct is obviously the ideal way to shoot a photo. But sometimes, there are situations with uneven lighting where you must over or underexpose your image.
Overexposed photos are brighter, while underexposed photos are darker. So, overexposed vs underexposed: which is better? The answer may surprise you.
Overexposed vs Underexposed: How Do You Know If an Image Is Underexposed or Overexposed?
Underexposure or overexposure happens when your camera settings aren’t correct. Most modern cameras in auto mode will produce images with decent exposure.
In this series of photographs, I have purposely used settings to demonstrate:
- Underexposure (left)
- Correct exposure (middle)
- Overexposure (right)
I photographed this camera outdoors on a cloudy day. The tonal range between the darkest and brightest parts of the photo is not extreme. In the middle photo, only a few highlighted areas appear a little overexposed.
Wherever you stand on the subject of correct exposure, you should know how to tell if a photo, or parts of a photo, are underexposed or overexposed. Overexposure occurs when your camera’s sensor doesn’t record any details in the brightest parts of an image, which means the details in the highlights are lost.
Underexposure occurs when your camera’s sensor doesn’t record any details in the darkest parts of an image. Your camera is able to display information about detail loss. Or you can see it in software such as Lightroom or Photoshop.
The histogram is an easy way to view the exposure information or exposure level on your camera or computer monitor. Histograms show you a graphical representation of the tonal values in your photo.
If your histogram graphic is showing a spike at the left or right edge, this represents high contrast. This means you have underexposed and/or overexposed pixels. There will be no visible details in the extremely dark and/or light parts of the image.
Your camera may also have a highlight alert option for when you are reviewing your photos. In this view mode, you will see the areas of your photo with no highlight details flashing.
Some cameras allow you to manually set a limit for when the highlights will blink. So you must check this is set correctly.
This information will help you figure out if your exposure is acceptable to you. I do not believe that having detail visible in all the highlights and/or dark areas is necessary for every photo I take.
Here is a good example, I wanted the fishermen in this photo to appear as silhouettes. I also knew there would be no detail in the sun.
The contrast range in the composition is just too great for my camera’s sensor to record detail in both the darkest and brightest areas.
You can see the histogram spike on both the left and right, indicating there is no detail in the shadows and the sun. But I still consider this photograph to be well-exposed.
What Range of Tones Can Our Cameras Record?
Our eyes can see a broader range of tones than most cameras can record. The human eye is capable of seeing about 30 stops of light. This is the “static contrast range.”
At any one time, we can only see about ten stops of light. This is the “dynamic range” of our eyes as it changes over time. Our brains constantly make adjustments, so what we see is “well-exposed.”
Modern digital cameras vary in how many stops of light they can capture. The best full frame cameras capture around 15 stops in test situations. But some claim this differs in the real world.
The most extreme range is limited to the lowest ISO setting. At higher ISO settings, the dynamic range is reduced.
This photo of a market vendor in Mandalay, Myanmar contains detail in the majority of the image because the tone range isn’t very broad.
No matter what camera you use, you need to make decisions concerning proper exposure. When taking photos in high-contrast situations, when the light is harsh and bright, you need to make more careful choices.
Your eyes may be able to see detail in the highlights and shadows, but your camera may not be able to record as much as you can see.
How Do You Choose Your Exposure?
To properly expose your image, you need to be in control of your camera.
I prefer to set my exposure using manual mode. This gives me more control and accuracy with the camera settings and exposure adjustment than if I am using any of the auto exposure modes.
When the camera is in any of the auto or semi-auto exposure modes, it’s programmed to give a correct exposure based on middle grey.
Unless you override these settings, you won’t have much control over how your photo is exposed. In high-contrast situations, the camera in auto mode wouldn’t expose the photo as well as a knowledgeable photographer in manual mode.
This photo of fishermen on Inle Lake in Myanmar may have resulted in an exposure like this with an auto exposure setting.
Including the sun and the sun’s reflection in my composition increases the tonal range dramatically.
The digital sensor cannot record detail in the brightest and darkest areas in the same exposure because the tone range is too broad.
I chose to expose this photo so there was some detail in the shadows and none in the sun and its reflection.
I used my spot meter to read the light from the nearest fisherman’s shorts. My exposure was at 1/2000 s, f/8, and ISO 400, which was a little less than my exposure meter indicated as correct.
I chose to underexpose a little so the two men appeared somewhat as silhouettes. In high-contrast situations, you must carefully choose how you make your exposure reading. This will influence whether your photo is correctly exposed in the most important parts of the composition or not.
In the photo above, I wanted some detail in the fishermen and the water. I also wanted some color in the sky. That is why I took the exposure reading from his shorts, which were a fairly neutral tone. Had I taken a spot meter reading from his white shirt with the aim of seeing it white in my photo, most of the photo would have been overexposed.
Even though his shirt is white, all I can see of it is in shadow because the sun is behind it. The shirt will not show as being pure white because it is reflecting less light than if the sun was behind me.
Find a midtone to take a reading from. This will help you choose the best exposure settings for your image.
What Is Middle Grey and Why Is It Important?
Middle grey is the tone halfway between black and white. Exposure meters are calibrated to this standard tone. When you compose a photograph with extremely light and dark areas, you won’t have an exposure that is correct for every section of the photo.
You will have a loss of detail in the highlights and/or dark areas. This is because the light value in those areas is too far removed from middle grey.
Here is an example with three exposures of the same subject with hard lighting and three in soft lighting.
I have taken screenshots from Lightroom with the highlight and shadow clipping turned on in the Develop module.
I took all the photos in the top row at f/16, ISO 100, and various shutter speeds.
The bottom row of photos, which I took on a cloudy day, shows the differences when photographing in lower contrast conditions. I took those at f/11, ISO 400, with the same varied shutter speeds as the top row.
The orange represents overexposed areas. The blue represents underexposed areas.
The middle photos are the closest I could get to an exposure with minimal highlight or shadow detail lost. You can see some detail loss in the darkest areas. There’s also a tiny amount of highlight detail lost on the lens.
How much detail you lose or keep varies from camera to camera. It depends on the quality of the sensor. Modern sensor technology allows you to capture a much broader range of tones on either side of middle grey.
This means there’s a smaller chance of overexposed and underexposed photos. A modern sensor is able to record more detail in darker and lighter areas of a composition.
Use Underexposure and Overexposure For Mood
You can influence the feeling in your photos by purposely choosing how your set the exposure.
Underexposing part of a photo can create more drama and intensity in a photograph. Overexposing will produce a much softer, gentler look and feel.
Look at these two very different exposures of this frangipani flower.
My exposure settings for the lighter image were 1/60, f/2.8, and ISO 400. I exposed the darker image at 1/250 s, f/2.8, and ISO 400.
I also post-processed them differently to accentuate the different moods I wanted to convey.
Boost It in Post
Modern camera sensors are so much more capable of capturing a broad tonal range than film ever has been able to.
This means that if you want to render images as underexposed or overexposed, you may need to use post-processing techniques to assist you in the amount of light that you want to have.
In Lightroom and similar photo processing software, you can accentuate the contrast levels. Drag the Black and the Shadow sliders to the left to make dark areas of a photo even darker.
Sometimes the Dehaze slider will help darken up an image. Dragging the Exposure slider to the left will affect the whole of the image. Adding contrast in this way will make photographs look as if parts or the whole picture is underexposed.
Be careful if you are making extreme changes. Taking any of the sliders to their extremes can cause an image to start looking unrealistic. Visible posterization can appear in dark areas which are not completely black.
In this photo of a novice monk in a temple in Baga, Myanmar, I measured the exposure from his face. In the original on the left, there is detail visible in his skin and much of the background. When I post-processed the photo, I added contrast by dragging the sliders in Lightroom.
Alternatively, dragging the Highlights and Whites sliders to the right will brighten the lighter areas in an image. Similarly, you can use the Dehaze slider by dragging it to the left. Dragging the Exposure slider to the right will lighten the entire photo.
Conclusion
Any decent-quality digital camera is capable of producing an acceptably correct exposure.
Choosing the darkest area of the composition to take an exposure reading can mean the lightest areas of the photo are overexposed. Choosing the lightest area of the image to make an exposure reading from can mean the darkest parts will be underexposed.
If you want to take perfectly exposed photographs all the time, you need to consider the contrast range. That is one of the most important photography tips for good exposure.
Compositions that are low contrast make it easier to get an even exposure. But in high-contrast situations, you’ll have a harder time getting an evenly exposed photograph.
Concerning yourself too much with making perfectly exposed photographs can lead to rather dull images. If there’s little contrast, the mood will also be missing. So always keep using contrast to your advantage in mind.
