Skip to main content
K12 LibreTexts

5.1: Quality of Light

  • Page ID
    3124
  • This lesson will help you learn and practice Quality of Light. In Get the Basics, you'll get explanations and photos to build understanding. In Explore, you'll find additional online resources to learn more. It's important to review and learn from these resources also! You'll have opportunities to practice in Build Your Skills. Finally, answer the questions in Record Your Findings at the end of this topic. Be sure to include information you learned from the Explore resources.


    Get the Basics

    Light is essential to photos. In fact, photography is the process of capturing light. So, what can happen if there's too little or too much light?

    If too little light reaches your digital camera's sensor, the results will produce photos that are too dark or even black. Three things affect exposure: shutter speed, aperture, and ISO (a rating for sensitivity to light). Your digital camera may not have ISO settings, or you may be using a smart phone with only scene modes. remember scene modes? They are auto settings that preset one or more of the exposure variables. This lesson addresses two of the exposure variables: shutter speed and aperture. If your shutter speed is fast and the aperture is small, too little light may reach the camera's sensor. This can also happen in auto mode if there's just not enough light.

    In this photo, the sky is overcast, and there is too little light. The photo looks dark, flat, and dull. The term for this is underexposed.

    overcast and dark day in the city


    Here's an example of a very underexposed photo. The photo is so dark that it's hard to see the person.

    dark underexposed photo of a person


    You see what can happen if there's too little light. What about too much light? Too much light can produce a photo that's way to bright. The term for this is overexposed. If a photo is way overexposed, the bright parts of the photo can appear all white with no details. This is called blown out. Overexposure can occur if the shutter speed is too slow and/or the aperture is too large. It can also happen in auto mode if there's just too much light.

    In this example, notice how the dogs and the background are so light that they lose all detail and run together (pun intended). Note: this photo has been edited to appear overexposed and blown out.

    sled dogs in action


    Here's another example of an overexposed, blown out photo. The background is totally white, and the bright areas of the blossoms blend with the background.

    overexposed, blown out photo of blossoms

    Explore

    Take a quick look at the same subject photographed three ways - underexposed, correctly exposed, and overexposed - at Photographic Examples of Exposure from DigicamGuides:
    http://www.digicamguides.com/learn/exposure-examples.html

    Now, learn more about how shutter speed, aperture, (and ISO) work together at The Ultimate Beginner's Introduction to Exposure from tuts+ Photography. Focus on shutter speed and aperture, and check out the examples in the "Putting It All Together for the Perfection Exposure" section:
    http://photography.tutsplus.com/tutorials/the-ultimate-beginners-introduction-to-exposure--photo-3028


    Build Your Skills

    To build your quality of light skills, you're going to shoot photos that have too little or too much light - two photos of each.

    Review your quality of light photos. Select ONE photo for EACH too little and too much light. Share your photos with your teacher, and be prepared to discuss how they show what you’ve learned. Download your photos to a computer to keep them for the portfolio you’ll create in the end-of-course final project.


    Record Your Findings

    • What can happen to a photo when there is too little light?
    • What can happen to a photo when there is too much light?
    • What does is mean to be underexposed? Overexposed?
    • What does it mean for a photo to have an area that's blown out?
    • Describe how the quality of light in each of your selected photos affects the appearance of the photo.

    References

    Image Reference Attributions

    [Figure 1]

    Credit: Daniele Rossi; September 21, 2008
    Source: https://www.flickr.com/photos/danielerossi/2877868812/

    [Figure 2]

    Credit: Ahmad van der Breggen, January 3, 2007
    Source: https://www.flickr.com/photos/ahhhh/346221751/

    [Figure 3]

    Credit: flickrolf; December 14, 2008
    Source: http://www.flickr.com/photos/rolfnoe/3110508439/

    [Figure 4]

    Credit: Eric, April 8, 2008
    Source: https://www.flickr.com/photos/ejpphoto/2432682634/