That's mostly to do with the direction of the light from the flash and how bright it. For example if you can make use of a bounce flash you can get a lovely so

That's mostly to do with the direction of the light from the flash and how bright it. For example if you can make use of a bounce flash you can get a lovely soft fill light. Light coming from very close to the axis of the lens as the dominant light source is going to make your scene look very flat. It works well for a day light fill a few stops down but generally looks a bit crap as the only light.