A single Flash (on camera will create hard shadows, because it is a small sized source of light. The only way to soften the light, is to make the source of light larger. One of the easiest ways of doing this with on-camera flash, is to bounce it of a reflective surface. This is no great secret or revelation. But using it successfully is dependant on you understanding a few basic principles.
If you bounce the flash off a surface (to the side of you, or behind you, or off a ceiling), then the relative size of the light source to subject is much larger than if you had shot with the flash straight on. There is a world of difference in the way your subject will be light up.
Things to think about when bouncing
The first thing to think about is: “What colour surface am I using to reflect (bounce) my light off ?”. Non white surfaces will affect the colour temperature or your light source, causing a change in the colour cast e.g bouncing off a surface that is painted blue will cause your photo to look cooler. Whereas a beige surface will reflect a warmer colour temperature.
The second thing is: “How reflective if my bounce surface?”. I will only cover this in brief here, as I want to do a few blogs simply about surfaces and how they reflect things. But think about how dose the surface your using reflect or absorb light?. e.g. Wooden, metal, glass, shiny or mat surfaces (to name a few) all reflect light differently. Some may absorb a lot of light, rendering your flash practically useless. Others may simply directly reflect the light at the opposite angle to that it came from the angle of reflectance = angle of incidence. And yet another type spray the light all over the place.
The third thing is: Don’t forget the “Inverse square law” (see my last blog). When you bounce your light it has to travel further there for you will need more power. You have to be aware of how close you are to the subject, and how far away your bounce surface is,
The forth thing you should know is : The angle of your strobe’s head. Keep in mind that the intended result is to have no discernible flash shadow. If your flash head is set to shallow or to deep, you will either light your subject wrong or worse not at all. Shooting with an “Omnibounce” at 60′ (or 45′), shouldn’t be a default way of using flash. For the best result, some thought needs to be put into how you use flash and the results you want.