Dark Field Lights provide illumination that is projected at a shallow angle to the imaging surface, 45 degrees or less. Typical applications include reflective flat surface defect or edge detection, where the majority of the light may reflect away from the camera on the flat, featureless surface but defects may scatter the light to the camera, creating feature appropriate contrast. Dark field illuminators can be dedicated ring lights, or any general bar or spot light oriented at low angles of incidence, depending on defect orientation. Very low angle dark field ring lights must be deployed at close working distances to be effective.

Bright Field Lights provide illumination directly onto an object, at angles of incidence above 45 degrees from horizontal, creating distinct shadows or general purpose illumination depending on subjects features.. This type of lighting is effective when used on objects requiring high degrees of contrast, but may create unwanted specular reflections when directed at shiny or reflective materials because of the high angle of incidence. Working distances can be short to very long.