The trick is knowing what type of flare you want or what camera effect you are trying to simulate.
Glows are caused by bright light sources illuminating the surface of the object.
Depending on the type of surface and the intensity of the light source, the glow can range in size and shape.
Furthermore, atmospheric conditions can affect your perception of a glow.
For instance, a chrome bumper on a car can have an intense glowing halo if it is illuminated by bright lights.
That same bumper can appear to be just chrome in a normal or dimmer light situation.
Sunlight is an example where glows are perceived differently depending on the atmospheric conditions.
For instance, the sun on a hazy day appears to have a rather large glow around it, whereas on a clear day, its glow is much tighter and intense.
Glows are typically perceived at the source as well.
Lens reflections happen at the camera lens, but a glow occurs at the source object in almost every situation.
Lens Effects Flare accounts for this, but it also enables you to glow the source in a 2D fashion-that is, the glow is not occluded by objects that block the rays caused by the light source.
Glows rely heavily on the intensity and color of the light source itself.
For instance, a bright white light such as a car's headlight produces a more intense glow than a cool, blue, backlit sign.
In either case, you need to alter not only the color and density of the glow, but also the size and softness in order to get the proper glow effect.
Many aspects affect how you perceive subjects in real-life.
In the upcoming sections, you see how to mimic your real-world perception of glows and flares using the Lens Effects Glow and Flare modules.