The key is controlled, flattering light. Rooftop daylight can work, but overhead light often creates harsh shadows in the eye sockets, under the nose, and under the chin, which is not ideal for business portraits.

If possible, use supplemental lighting so you can control the look. A simple portrait setup with strobes or continuous lights, plus a modifier like an umbrella or softbox, will give more polished results and let you keep ISO low for sharper files. Even a reflector can help by bouncing light back into facial shadows if you stay with natural light.

Also, prepare everything before your subjects arrive. Set up the background and lights in advance, then do a trial run with a friend so you can refine exposure, pose, and light direction ahead of time. That way, when the actual subjects arrive, the session is quick and confident.

In short: avoid relying on overhead ambient light alone, add fill or off-camera light if you can, and test the setup beforehand. Control and consistency are what make portraits look professional.