Which setting is typically used to create a blurred background in portraits?

Using a wide aperture is the preferred method for creating a blurred background, also known as bokeh, in portrait photography. A wide aperture (represented by a small f-number, such as f/1.8 or f/2.8) has the effect of narrowing the depth of field. This means that only a small plane in your image will be in focus, while the areas in front of and behind the focal point will become progressively more out of focus, resulting in a smooth, aesthetically pleasing background blur.

This technique is particularly useful for portraits, as it helps to isolate the subject from the background, drawing attention to them and enhancing the overall composition of the image. In contrast, a small aperture would deepen the depth of field, meaning more of the background would appear in focus, which can detract from the subject. A very high shutter speed is used for freezing motion rather than controlling depth of field, and a low ISO setting influences the camera's sensitivity to light rather than depth of field or background blur.