Note: All that is discussed below applies to outdoor portraiture of women only.
Below is an example of front-lighting picture, that is, the model is facing the sun.
One problem of front-lighting is that the shadow can be distracting, as you can see in the picture above. Another problem is that the model may squint her eyes when facing the sun.
Here is a backlighting photo, that is, the sun is behind the model.
One issue with backlighting portrait is that the subject’s face may be underexposed, i.e. too dark. This, nonetheless, can be overcome by firing the flash or reflecting sun light using a “reflector”.
There are several advantages of backlighting portrait. Firstly, the shadow problem is minimized. Secondly, sun light reflected off the model’s hair, making the picture more pleasing. Thirdly, the use of flash or reflector, apart from brightening the face, also creates “catch lights” in the model’s eyes, again enhances the picture.P/S There are ways to enhance a front-lighting photo, but these are beyond the scope of this post.