Using off camera flash can have a significant impact on your photos. Early this morning around 11am Steph and I went down to the park so that I could play around with my new reflector that I purchased. The sky was fairly overcast which makes for nice soft light for photography when you are shooting against a solid background such as a wall. However, shooting against the sky would be nearly impossible without a double exposure composite photo or using a significant grade graduated polarizing filter. Here is a photo of the sky over Boston (southie mostly) as exposed correctly for the subject.
(click on the images to view the larger versions)