This week, we shall explore in more detail in the second part of understanding exposure and the concept of depth of field.

Aperture
The Aperture is the opening in your lens that allows light to pass through. Think of it as a pupil of your eye. The amount of light is controlled by “f/stops”. As you can see in diagram 1, a shallow f/stop, usually f1.4, will allow plenty of light to pass through your lens. This has an effect of shallow depth of field, which simply means that if the focus is in the front, the background will become blurry. This is ideal for portrait photography.

On the opposite end, f22 restricts light and makes the foreground and background sharp. This is great for landscape shots where you want a sharp foreground and background.

Try
The best way to learn this is to try photographing using all the f/stop. Place two objects front and back on a table, separated by 10 inches. Make sure you can see both objects when you photograph. Set your camera to Aperture mode and the camera will adjust the other elements (Shutter and ISO) automatically. Focus on the front object and photograph using the widest Aperture of your lens. Change to the next f/stop and take another photo. Keep doing this till you reach f/11. You should see that the background object starts out blurry and keeps getting more in focus as you change your aperture.

Tip
Use the Aperture setting if you want to blur out either the background or foreground. This helps to draw the viewer’s attention to the point of focus. This is great for portrait, macro or food photography. Image 2 was shot with a wide aperture at f/1.4 making the background blurry so that attention is on the ring.

For a landscape image, where the aperture is f/11 in the image below, almost everything is in focus and visible.

ISO
ISO is a level of sensitivity of your camera to available light. The lower the ISO, usually 100 or 200, the less sensitive it is to light while a higher ISO is more sensitive. The sensor on your camera is responsible for your ISO sensitivity and cost a big part of the camera. Think of it as the brains of your camera. Most modern digital cameras have advanced sensors that can capture low-light images without a flash. The result of high ISO is grainy images, or in the photographic term, noise. Generally, noise is not flattering in an image, but you can use it to produce an image that looks vintage..

How Aperture, Shutter and ISO affect each other can be seen from this Exposure Trinity diagram. I shall continue with Shutter in my next article.

Photo critique
Feel free to send in your photos for a constructive critique and I will publish them in the following articles. There are no right or wrong answers; just suggestive ways to improve an image. You can send them to jeff@studio81.co.nz

About the author

Jeffery is the owner and photographer at STUDIO81 photography which has 2 locations i.e. Newmarket and East Tamaki. STUDIO81 is one of Auckland’s leading portrait photography studio and specialises in modern glamour transformation. Jeffery is an award winning photographer and NZIPP Master of Photography.