Presented by Luc Letendre Photography in cooperation with the Catholic District School Board of Eastern Ontario & St. Thomas Aquinas Catholic High School

A. Aperture: aperture and light The aperture (the size of the lens opening) controls the brightness of the light that reaches the film/sensor. The size of the aperture works like the pupil of an eye; enlarging or contracting the aperture admits more light or less. Aperture is indicated by its f- number or f-stop. Figure 3.1 The size of the lens opening – the aperture or f-stop – controls the amount of light that passes through the lens. The lens shown here has apertures from f/2 to f/16. Each setting is one “stop” from the next. The bigger the f-stop number, the smaller the lens opening and the less light is let in. On this lens, f/2 is the largest opening and lets in the most light. As the numbers get bigger (4, 5.6, 8), the aperture size gets smaller and the amount of light admitted decreases.

A1. The Aperture: settings Figure 3.2 On Nikon models, the aperture priority setting is represented by the “A” on the Mode Dial. Figure 3.3 On Canon models, the aperture priority setting is represented by the “Av” on the Mode Dial.

Figure 3.4; 3.5 & 3.6 Areas on your camera where you can locate aperture setting indicators. The viewfinder (above left), the LCD display located on the back end of your camera (above right) and on the data panel (right). A2. The Aperture: aperture setting indicators

A3. Aperture: The Aperture and Depth of Field Figure 3.7 Depth of field is the area from near to far in a scene that is acceptably sharp in a photograph. As the aperture changes, the depth of field changes too. When the lens is set to its widest aperture, in this case f/2.8, the depth of field is shallow or you may equally say that the zone of sharpness is shallow. When the lens is stopped down to its smallest aperture, here f/11, the depth of field increases. Almost the entire scene is now sharp.

A4. Aperture: The Aperture and Depth of Field Figure 3.8 & 3.9 The photograph on the left was taken using a lower aperture number (wider aperture opening) such as f-2.8 resulting in shallow depth of field (small area of the photograph in focus). The photograph on the left was taken using a larger aperture number (smaller aperture opening) such as f-22 resulting in greater depth of field (most if not all areas in the photograph are in focus). The photographs were taken using the exact same camera settings with only changes to the aperture setting.

A5. Aperture: Focus and Depth of Field Figure 3.10 In figure 3.10, the photograph on the left (numbered 1) was taken by focusing on the card in the centre using a lower aperture number, in this case f-2.0 resulting in shallow depth of field. This is the reason why the card in the front and in the back are out of focus. The photograph on the right (numbered 2) was still taken by focusing on the card in the centre however a larger aperture number was used, in this case f-22 resulting in greater depth of field. This is the reason why the entire image is in focus. 1.2.

A6. Aperture: Focus and Depth of Field – controlling depth of field Figure 3.11 Sharpness and Depth of Field The smaller the aperture, the greater the depth of field. Here the photographer focused on the front clock. Far Left: with a wide aperture, f-2, the depth of field is relatively shallow; other clocks that are farther away are out of focus. Left: using the same focal length and staying at the same distance, only the aperture was changed - to a much smaller one, f-16. Much more of the scene is now sharp. Changing the aperture is usually the easiest way to change the depth of field. The shorter the focal length of the lens, the greater the depth of field. Far left: with a 180mm lens, only the first subject is sharp. Left: with a 50mm lens at the same distance, set to the same aperture, and focused on the same point as the previous shot, the person in the background is sharper. Notice that changing the focal length changes the angle of view (the amount of the scene shown) and the magnification of objects in the scene. The kind of picture has changed as well as the sharpness of it. The greater the distance form the subject, the greater the depth of field. Far left: with the lens focused on the subject in front about 3 ft away, only a narrow band from near to far in the scene is sharp. Left: using the same focal length and aperture, but stepping back to 10 ft from the subject and refocusing on her made much more of the scene sharp. Stepping back has an effect similar to changing to a shorter focal length lens: more of the scene is shown, and more of the scene is sharp.

B. Focal Length Figure 3.12 The effect of increasing focal length while keeping the same lens-to-subject distance is an increase in magnification and a decrease in angle of view. The diagram at left shows the angle of view of some of the lenses that can be used with a 35mm camera. Figure 3.13 & 3.14 The images above illustrate the results obtain by focusing on a subject and changing the focal length of the lens. Notice the changes between using a wide angle (28mm) focal length (upper left photo of the image on the right) versus the results obtained by using an increased focal length of 70mm (lower right photo of the image at the right). 28mm 35mm 50mm70mm

C. Camera Basics Challenge Reviewing the concepts of shutter speed, shutter speed and movement, aperture, depth of field and focal length.

E. Suggested Exercises 1.Shallow depth of field a)Set your camera lens to the smallest f-stop number and longest focal length it contains. Proceed to photograph a series of objects at the closest distance possible (your lens should be able to focus on a particular area of the subject). Notice how the long focal length, small f-stop and close distance create images with very shallow depth of field or areas of focus. 2.Sharp photographs or greater depth of field a)Photograph a second series of pictures with the reverse settings to those above – i.e. use wide-angle lens (or zoom setting), large f-stop number and medium ‘subject-to-camera’ distance. Notice that the images you create with these settings have large zones of focus extending from the foreground into the distance.