The lens flare effects let you control where and what the lens flare affects in the scene.
Brighten: Lets you set an overall brightness that affects the whole image. When a bright effect, such as a lens flare, appears in an image, the whole image should appear brighter. This effect is available only when the Brighten option is enabled under the Render section of the Preferences dialog box.
Dist Fade: Causes the effect of the lens flare to fade with its distance from the camera. This option is used only when the Dist Fade button is turned on. The values are in 3D Studio MAX world units.
Cent Fade: Fades the secondary flares near the center of the row of flares along the main axis of the flare. This is an effect that can be seen in many lens flares seen through a real camera lens. This value is in 3D Studio MAX world units. Cent. Fade is available only when the Cent Fade button is active.
Dist Blur: Blurs the flare based on its distance from the camera. This value is in 3D Studio MAX world units.
Blur Int: Controls how strong the blur is when applied to the lens flare.
Soften: Provides an overall softening effect for the lens flare.