Lowel Lighting have posted another excellent lighting article, this time explaining how soft lighting affects the subject of your photo/video.
Soft Light Explained
A soft light source would be one that appears larger in relative size than the subject being lit. Being larger than the subject, the light source is covering it from a greater angle and, as a result, filling in more of the potential shadow areas.
This effect is called wrap around lighting, because the coverage of the light source appears to wrap itself around the subject. A light source that is smaller than the subject cannot wrap light around it and fill the shadows.
While shadowless, or flat, lighting can be a legitimate lighting style, light that is too soft can rob an image of its sense of dimension and depth. The shot lit by the overcast sky is an example of this.
Don’t forget that your image is 2 dimensional, and you are giving the illusion of depth thru the creative use of shadows and contrast. These details are also what give the viewer clues about the form and textures in fabrics and food; or surfaces like weathered wood and rough stone.
Lighting is not always either hard or soft. There is a whole range of creative possibilities in between these 2 extremes. Note the visible differences in the shadows behind the 2 statue images above. Moving the soft light back created a smaller source, making the effect of the output harder and the shadows stronger.