A control for a controllable optical device, such as an auto-darkening
lens (ADL), such as used in welding helmets, respirators, or other
device, includes a sensor sensing the direction of incident light and a
control circuit responsive to incident direction information to provide
for control of the optical device. Based on at least one of incident
direction of light and light intensity a the shade characteristics of the
ADL or the like can be controlled and maintained while a person wearing
the ADL may move the head to different orientations. Several fixed
photosensor arrangements and dynamic systems may be used to sense
incident light direction and whether the incident light is a point
source. A method of detecting direction of incident light and whether the
incident light is from a point source, and of controlling an ADL or the
like based on direction and/or intensity of incident light.