Depth of Field is one of the main creative tools in photography. It’s where you get to control what’s sharp and what’s not in your photos.
But there’s more to controlling depth of field than just apertures.

By understanding and using depth of field you can get everything in your photos pin sharp, make messy backgrounds disappear and emphasise the subject.

The main control of your depth of field is with the camera’s apertures. Those are the numbers beginning with ‘f’ in the LCD which go something like…

f3.5 f5.6 f8 f11 f16 f22 …….

Apertures can be controlled either manually or by using the A (Aperture Priority) setting on the command dial. Many camera makers call it AV (Aperture Value) but it is exactly the same thing.

The higher the ‘f’ number you set the greater the depth of field in your picture will be. Another way of saying it is that more of your picture will be in sharp focus with high 'f' numbers. This is great for landscapes or macro close ups.

The lower the ‘f’ number you set the shallower the depth of field will be. Use low 'f' numbers for shallow depth of field when you want to have a sharp point in the picture but have a blurred background / foreground.
So …

• f3.5 = shallow depth of field
• f11 = middle depth of field
• f22 = masses of depth of field

But there’s more - apertures aren’t the only thing controlling depth of field. The length of your lens makes a massive difference.

The Longer the length of lens then the smaller the depth of field, also the greater the magnification (as in Macro) the smaller the depth of field.

Here are the simple ‘Golden Rules’ of depth of field.

Low ‘f’ numbers have shallow depth of field

High ‘f’ numbers have greater depth of field

With a short lens you can get lots of depth of field

With a long lens you get only a little depth of field