I have always loved working with just one light source while learning how to get the most out of the quality of light available.  The sun is a very unique source of light to expose for.  It is truly amazing to notice all of the color and quantity values the Earth gets throughout the day depending on the atmosphere.  As a working pro photographer I like to schedule sessions outdoors within the best times of the day for the best quality of light.  The difficult part of scheduling sessions like this is the unknown. Our weather here in New Orleans plays an acting role when we photograph outside.

The time of day is not only important for the sunlight but also the crazy heat and  humidity.  OUCH!!!!!  Today was 96 and the air was  filled with humidity as if you were breathing air inside a hot sauna.  The most important reason why I love working with natural light is for the mood and ambiance of the scene.  The above images are all exposed for the sunlight only.  The 1st image was the end of the day sun entering the room being filtered by the windows. How the shadows are exposed is important here.  If you underexpose the shadows are too dark.  If you overexpose the image looses the mood.
The 2nd image I used the sunlight for my highlights instead of the main light.  My brain sees the options of how to use the light I'm seeing in front of me.  The sunlight is behind the client allowing the sun to shine across them giving highlights in the hair and shoulders.   The best thing to do is walk around your client first and see the options you have for exposing the image.  Doing this one step will also add creativity to your images because you'll see options you didn't see before. The world is in constant motion so move with it.

The last image was actually during the middle of the day which is usually the worst time of the day to shoot.  The building however does a fantastic job of becoming one large soft box depending on where you put your subjects.  I was totally fine overexposing the window light because I wanted to showcase my clients not the trees outside. 

Natural Light to expose for:
direct light
shade
highlights
shadows and where do they fall in your image!

The next time you are outdoors pay attention to the above and you'll start seeing the world in a new light.   no pun intended.  :)