Using Histograms to Adjust Exposure
Students will learn what a histogram is and see examples of correctly exposed, overexposed and underexposed images to study histograms and how the camera’s light meter works. A hands-on lab activity gives students the opportunity to analyze the relationship between camera settings and the histogram generated in a variety of light situations.
- Students will understand the importance of exposing images correctly with the camera and available light during a photo shoot rather than relying on editing software such as Photoshop to adjust images later.
- Students will be able to interpret in-camera histograms to determine whether an image has a proper exposure.
Common Core State Standards
|CCSS.ELA-LITERACY.WHST.9-10.6||Acquire and use accurately general academic and domain-specific words and phrases, sufficient for reading, writing, speaking and listening at the college and career readiness level; demonstrate independence in gathering vocabulary knowledge when considering a word or phrase important to comprehension or expression.|
|CCSS.MATH.CONTENT.HSF.IF.B.4||For a function that models a relationship between two quantities, interpret key features of graphs and tables in terms of the quantities and sketch graphs showing key features given a verbal description of the relationship.|
Materials / resources
Digital SLR cameras (or smartphones with camera apps)
1. Making connections — 5 minutes
Begin by showing an especially dark or noticeably overexposed image to ask students what they notice. Invite students to share what they could do to prevent images like this. It’s likely that someone will suggest editing the image to adjust, such as opening the image in Photoshop and using Levels or Curves. Introduce the idea that exposing an image correctly within the camera is best. Explain that today’s lesson will show students how to study a histogram within the camera in order to expose the shot correctly.
2. Direct instruction — 20 minutes
Use the slideshow to present the material. The notes section of the slideshow offers specific guidance regarding the histograms and photos used as examples on each slide, so be sure to review the presentation ahead of time. Students should take notes. Guide related discussion and check for understanding.
3. Practice — 25 minutes
Distribute the handout and provide an overview of what students will do.
The lab requires students to work in partners. Depending on your classroom setup and the number of cameras available, you could structure this as a small group activity instead, or you could pair this with another lesson so only half the class is using cameras at a time. In addition, students with smartphones may choose to search for camera apps that allow for the use of histograms (such as ProCamera, Camera Pro Live Histogram and Blux Camera Pro) as an alternative.
If you have advanced photographers in the class, they can check in with each partner group to offer guidance as needed.
Return to the large group and discuss results as a class. You may choose to collect the completed lab worksheets to check for understanding or for part of a daily grade if necessary.
4. Assessment — 10 minutes
Administer the exit ticket quiz.
As an extension or advanced follow-up activity, students can use histograms in Photoshop Levels to adjust exposure after this lesson or with any remaining class time.
For students who need remediation or a simpler way to demonstrate understanding, use the matching cards provided instead of the exit ticket quiz. Print and cut the two pages into individual cards of images and their histograms. Match the photo with its histogram.
(Answers: 1C, 2F, 3D, 4A, 5E, 6B)