Every camera lens is bound to have a level of error in it. This leads to luminance drops and patterns such as lens flares, glares, and chromatic aberrations. Some lenses are used to capture images with distorted or enhanced perspectives, such as the fish eye lens and spherical lens. Adding these effects to a CG image will enhance the realism of it. Blender provides a very wide range of nodes to achieve these distortions.
Glare is a discomfort of vision in the presence of a bright source of light. This is seen in any photograph with a light source in its content. This phenomenon exhibits streaks, discs, or foggy rays shooting away from the source. Adding these effects adds realism to the image.
Blender's Glare node provides multiple options to simulate this behavior. The following screenshot illustrates the four types of glares available in Blender's Glare node:
The Lens Distortion node provides perspective alteration procedures with a chromatic aberration effect, that is, a distortion due to failure of the lens to focus all colors to the same convergence point.
All these options can be used in cohesion to obtain multiple lens distortion effects, thus simulating a real world lens and adding more realism to the image.
The following screenshot illustrates the effects that can be obtained using this node. Observe the black/empty pixels created at the bottom corners due to distortion of the perspective.
The Despeckle node simulates an effect of shattering the pixels. Threshold can be used to limit the effect based on the luminance of the image. Alternatively, a gray-scale image can be connected to factor input to control the effect of the Despeckle node, as shown in the following screenshot:
The Filter node implements various image enhancement filters, producing a variety of image distortion effects. The following is a list of filter types available in this node, followed with a screenshot: