What & Where is the Aperture?
Your Camera’s Aperture is one of three fundamental settings required to produce a photograph with a good level of light (Exposure).
The Aperture is a series of overlapping blades that form an iris inside your Camera’s lens (below). The range of sizes the Aperture can offer will be determined by the lens itself.
What controls am I looking for?
You are looking for numbers (called f-numbers) that look like this… 2.8, 4, 5.6, 8, 11, 16, 22 (you may have slightly more or less numbers depending on your camera). You should have a screen either on the top or back of your camera that will show you the number you are set to.
How to I Control the Aperture?
The Aperture is controlled by a button or scroll on the body of the camera. It is different on every camera and you will need to find it (use your camera manual if needed). This diagram shows you how to change it on a Canon 60D, it may be similar on other Canon models.
How does Aperture Affect the Photograph?
The brightness (exposure) of the photograph is affected by the changing size of the Aperture. This change allows you to control how much light you let in, however this will have another visual effect on the photograph (as shown below).
The amount of the photograph that is in focus (Depth of Field) will also be affected by the the changing size of the Aperture.
A Larger area of your photo will be in focus (left) when you Increase the Aperture number (i.e: 16 or 22). A Smaller area of your photo will be in focus (right) when you Decrease the Aperture number (i.e: 2.8 or 4).
These photos were taken on the ‘Aperture Priority’ Setting, so the camera corrected for the light change using the Shutter Speed (next post) to keep the exposure correct.
What is Aperture Control Useful for?
A huge advantage to controlling your aperture is being able to choose a small portion of a scene to be in focus. For example, if you are taking a portrait of someone and the background is very busy, you can use a smaller aperture number to throw the background out of focus and make the person stand out (below).