When your light comes from a broad source, such as a big window, it is a soft light. When the light comes from a narrow source, such as a flashlight, it is considered a hard light. When you utilize a broad light source, your shadows, texture, and contrast will be softer because the light is distributed more gradually across the subject. A hard light maintains a narrower angle of light, focusing it in a smaller area, thus making the places outside of the light path darker and textural.
Now let’s talk about the distance of your light in relation to the subject. When a light source is close to your subject, it will be softer than if it is far away. Why? Because the closer it is, the broader it will become.
When would you prefer one over the other? If you are taking a portrait, lighting is most flattering when it is broad and close to your model. It smooths out wrinkles, and makes flaws less noticeable.
However, if you want to emphasize the character of a well-lived face, such as a sailor or athlete, use a narrow light from a good distance away. This will give more texture and contrast with shadows to the planes of the face. Click on this link to see an example of a hard light portrait.