When working with one speedlight outdoors in daylight, logic dictates that you need to find the shade if you want to create a nice quality of light.

This is because you only have one light, which a) needs to do all of the heavy lifting, and b) is not very powerful. Which means that you tend to go soft—and close—with your one light.

So one light can be limiting. But as you'll see, a second light can open up some pretty neat options. Read more »

http://strobist.blogspot.com/2018/01/slc-2l-01-owning-sun-with-two.html