Page 44 - Learning How to Photograph with your DSLR Camera 2nd Edition Jan 2021

This scale can be quite confusing to some when learning about aperture. You may have
seen these numbers on older film lenses with an aperture ring. Today they can be seen
on the LCD screen of your modern DSLR camera.

Figure 20 The f/stop Scale

The f/stop scale is a sequence of fixed numbers starting with 1.4, 2, 2.8, 4, 5.6, 8, 11, 16,
and 22. If you notice the numbers increase on the scale. As the number increases the
opening becomes smaller. This is called stopping down the aperture. As the numbers
decrease the opening becomes bigger and is referred to as opening up the aperture or
shooting wide open.

A better way to think of these numbers is as fractions. For example, we know that 1/2 is
larger than 1/22. The same is true that the opening at f/2 is much larger that f/22. This
is an easy way to remember what each change makes in the diameter of the aperture.

Not every lens will have all these apertures. You may also find other numbers not on the
standard f/stop scale. These are third stops. For example, after f/2.8 there may be f/3.2
which is a one third stop smaller and f/3.5 which is two thirds smaller than f/2.

Wide apertures like f/1.2 and f/1.4 can make the lens more expensive. These are
called fast lenses as they are ideal when shooting in low light.

How Aperture Affects Your Image

We are talking about Depth of Field (DoF). This is essentially how much is in focus from
the front to back of your photograph. Having a wider aperture like f/2, creates a very
narrow DoF. While a smaller aperture like f/16 will have more in focus from the
foreground to the background.

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