What is essential for achieving a blurry background in photography?

To achieve a blurry background, commonly known as "bokeh," using a wide aperture is essential. A wide aperture, which is represented by a lower f-number (such as f/2.8 or f/1.8), opens the lens more, allowing more light to hit the sensor. This wider opening not only gives you the ability to shoot in lower light conditions but also decreases the depth of field.

As a result, when you focus on a subject that is at a closer distance, the background becomes increasingly out of focus. This effect enhances the subject, making it stand out against a softer, less distracting background. While being close to the subject can also contribute to the effect, the key factor is the aperture setting, which directly controls the amount of background blur produced.

High ISO settings and high shutter speeds do not influence background blur in the same way. ISO affects the sensitivity of the camera sensor to light, and while a high shutter speed can prevent motion blur, it does not affect depth of field. Therefore, the use of a wide aperture is the most critical element in isolating the subject from its background by creating that desirable blur.