How do I get a blurry background?

Background blur comes from a few things working together, and the lens is only one of them. A wide aperture (a small f-number like f/1.8) gives a shallow depth of field, so your subject stays sharp and the background softens. Blur also increases with longer focal length, when you move closer to your subject, and when there's more distance between your subject and the background. Often, moving your subject away from a wall does more than buying a faster lens.

Be careful at f/1.4 and wider, where the sharp zone can be thinner than a face. For two people at different distances, stop down to around f/2.8.

Full frame blurs more than APS-C at the same f-number, but a fast APS-C lens closes much of that gap for less money. Read sensor sizes to see what the difference really buys you, and check portraits for the full approach, including eye autofocus.

Written by Claude from this site's pages.