Portraits live or die on a handful of decisions: how much of the background stays sharp, whether the eyes are in perfect focus, and whether the subject is lit in a flattering way. None of this requires exotic gear — it comes down to a few settings you can dial in before you ever press the shutter.
Aperture: Controlling Background Separation
A wide aperture (f/1.4–f/2.8) throws the background out of focus, isolating the subject — the classic "portrait look." A narrower aperture (f/5.6–f/8) keeps more of the scene sharp, which matters for group portraits or environmental shots where the surroundings tell part of the story.
- Single subject, blurred background: f/1.8–f/2.8
- Two or three people, same focal plane: f/4–f/5.6
- Group portrait, multiple rows: f/7.1–f/9
Wider apertures also demand more precise focus — at f/1.4, the zone of sharpness can be thinner than the depth of a face, so a hair's width of front-to-back movement can throw the eyes soft.
Focus: Keeping the Eyes Sharp
The eyes are the one part of a portrait that has to be sharp, even when everything else is soft. Most modern cameras have an Eye-AF or Eye Detection mode built specifically for this — turn it on for portrait work and let the camera track the nearest eye automatically.
Without Eye-AF, use a single focus point (not wide-area autofocus) placed directly on the near eye, and recompose only if your camera doesn't shift focus when you do. Continuous autofocus (AF-C / AI Servo) is safer than single-shot AF (AF-S / One Shot) if the subject is moving or shifting weight, even slightly, between shots.
Shutter Speed: Freezing the Moment
For a stationary subject, 1/125s is generally fast enough to eliminate both camera shake and minor subject movement (blinking, small shifts). For subjects in motion — kids, pets, candid moments — push to 1/250s or faster. Handheld with a longer lens, follow the reciprocal rule as a floor: shutter speed at least 1/(focal length) to avoid shake.
ISO: Adapting to the Light
Outdoors in daylight, ISO 100–200 keeps noise invisible. Move indoors or into shade and ISO 400–800 is normal; under dim window light or evening ambient light, don't hesitate to go to ISO 1600–3200 — modern sensors handle this cleanly, and a slightly noisy sharp photo beats a clean blurry one every time.
Lens Choice
Focal lengths in the 50mm–135mm range (full-frame equivalent) are the traditional portrait sweet spot: close enough to work with, far enough back that facial features aren't distorted by perspective. Wider lenses (24–35mm) require getting physically close, which can exaggerate the nose and forehead — useful for environmental portraits, less flattering for tight headshots.
Putting It Together
A reliable starting point for a single outdoor headshot: f/2, 1/250s, Eye-AF on a single point, ISO adjusted to whatever keeps that shutter speed and aperture — then check the EXIF data on your test shot to confirm the camera didn't quietly bump ISO higher than expected in changing light.