NIKON KNOW-HOW – CONTINUED

setting (such as the 18mm end of a kit lens) is good for keeping everything sharp, whereas to blur the background, you need to use a longer focal length, such as 55mm.

The third factor is the distance between the camera and subject. The smaller this is, the less DOF you’ll have. This is clear with macro work, when DOF all but disappears. But DOF extends the point of focus, as well as in front – so focusing on the most distant point won’t give you maximum DOF.

However, the three factors controlling DOF don’t always work in harmony.

You might decide to swap to a wide-angle lens to improve DOF. This makes your subject look smaller in frame. To fix this, you’d move closer, but this reduces DOF.

SNEAK PREVIEWS

Looking through the viewfinder of a DSLR doesn’t show the effect of changing aperture – it shows the view with the lens wide open, but predicting the end result isn’t pure guesswork. Many Nikon DSLRS have a DOF Preview button, which stops down the lens to the selected aperture.

Unfortunately, this darkens the image, making it harder to see.

With the electronic viewfinders of Z-series Nikons, not only is the lens always stopped down to the selected aperture, enabling you to judge DOF, but the brightness reflects the exposure settings, so you can see the image clearly. This is also true of using Live View on a DSLR. Indeed, some DSLRS, such as the D3500, don’t have a DOF Preview button, so you’ll have to use Live View if you want to get an idea of how much of your scene is in focus before you take the shot.