Which Aperture (F-Stop) to Use

For natural light portraits, this is a pretty easy choice—I use the lowest numbered f-stop my lens will allow. So, if the lowest number my lens will allow me to use is f/4, that’s what I use. Using the lowest numbered f-stop like this will help create that separation from the background by giving you that out-of-focus background that you generally want in natural light portraits. Plus, these low-numbered f-stops allow more light in the camera, and help a lot when you’re shooting in the shade, or under a tree, or in any low-light situation. So, when I’m shooting natural light portraits with my 70–200mm f/2.8, for my f-stop, I choose f/2.8. If I’m shooting my 85mm f/1.8, I shoot it at f/1.8. It’s an easy choice.