How do camera settings affect the final image, and how can we use aperture and shutter speed to take better pictures?

In this lesson, students use the area of circles and fractions to explore how to properly expose a picture, and how photographers use depth of field and motion blur to get the perfect shot.

### Students will

• Understand that increasing the aperture of a camera lens causes objects in the background to appear blurry
• For a given aperture, use the diameter to calculate the area of the lens opening
• Recognize that increasing the aperture by one “stop” doubles the amount of light
• Understand that shutter speed is the time that the film (or digital sensor) is exposed to light
• Given a correct aperture + shutter speed combination, find other combinations to correctly expose the image
• Explain how aperture and shutter speed affect how the final image looks
• Be able to analyze photographs and discuss likely shutter speeds and apertures

### Before you begin

Students should be able to calculate the area of a circle. Students should also be familiar with fractions, and be able to explain that 1/60 is twice as large as 1/120, and half as large as 1/30.