There are many factors to consider when you're planning an outdoor shoot, one of the major ones being how you're going to deal with natural light. One of the issues that's bound to come up while dealing with that big key light in the sky is how to find out which direction the light is coming from, which is especially important if you're planning on using it as a catch light. In this video from photographer Frank Donnino, we're shown how to use an everyday marble to determine where a light source will hit your subjects' eyes, so you can put them in the position that will give you optimal results.
In cases where the light is very directional, finding out where the light is coming from is easy. However, sometimes that's not the case -- maybe there's an over-abundance of light, maybe it's overcast. If you find yourself in that kind of situation, especially if your shot needs to be really precise, like in the example I gave earlier about lighting someone's eyes with a catch light, Donnino's marble trick definitely will be a lifesaver.
Now, some of you may already use this trick (as Donnino says in the video, younger people may not know about this), but perhaps this is a good refresher. As you'll see in the video below, he uses a 25mm marble, opaque or shiny (though he prefers shiny) to find out where the light bounces off of it. This is such a cool idea, because the marble is essentially representing an eye. The way he holds the marble is key as well, because he uses his thumb as a stand in for his subject's nose. This helps to visualize where exactly which direction your subject's face will be facing.
Check out Donnino's video below:
Have you ever used a marble (or something similar) like this on your own projects? Do you use other tricks to find out which direction light is coming from? Let us know in the comments.