Golden-hour portrait

The constraint that dominates here is subject isolation, and the light is your gift. At 70mm and f/2.8 with your subject two metres away, total depth of field is only about 8.8 cm — enough for both eyes on the plane of focus, and nothing behind them. The low, warm sun of the golden hour wraps the face softly and does the colour grading for you, so you can spend your attention on the eyes and the gaps in the background. Set aperture priority at f/2.8, let the camera solve the shutter, and put AF-C with Human-eye recognition to work.

Watch out for motion, not light. Your recommended 1/125 minimum shutter is fine for a still adult but not for a fidgety child or a breeze-blown strand of hair — raise the Auto ISO minimum shutter to 1/250 so faces stay crisp. And check the background before the face: at this depth of field a bright gap turns into a distracting blob, so move a step until it falls into shade.