This is a repeat, but one that needs repeating since I think we all want to achieve great portrait shots— even when it’s just a quick candid shot we’re grabbing before the cake is served or before the kids are leaving for school. And using shallow depth of field is a key to great portraits (along with expression, lighting, angle). Shallow depth of field, when the parts of the image in front of and behind the subject are out of focus, makes your subject pop off the image. The example here (a repost from the summer), for instance, shows the eye and smile in sharp focus, yet the tip of the nose, ear and hair are out of focus. Another advantage of shallow depth of field is that you can eliminate distracting backgrounds like indoor clutter, foliage, cars on the street, etc., It makes the background less defined with soft colors.
To get shallow depth of field, the key is to set your camera to the “A” mode: Aperture-Priority. You can leave your ISO setting at 200 or 400 (or higher if the lighting conditions are low) and leave your camera in autofocus. You will then use your thumb-wheel to dial in the smallest number you can, like F/2.8, F/3.5, F/5.6. Focus on the eyes of your subject, or the eye that is closest to the camera. Depending on how close you are to your subject and what lens you are using (telephoto lenses and closer proximity make the effect even more apparent), you will notice that the background is just soft to almost unrecognizable. If you want the photo to have some context of where you are (like cooking in the kitchen), then maybe F/5.6 is a better choice. But if you want the crowd in the background to go really soft, “open the lens wider” to F/3.5 or F/2.8 if you can.Please review the aperture download card here.