A multi-stage control for an auto-darkening lens includes a first detector
to detect initiation of welding and a second detector to detect
continuation of welding after welding has been initiated. The first
detector has relatively low sensitivity and fast response time; and the
second detector has relatively high sensitivity that can be altered as
may be necessary, relatively slow response time to allow opportunity to
determine whether welding is continuing as inputs indicative of welding,
and adaptive filtering to filter ambient effects and the like from such
inputs to avoid false detection of welding. A method of enhancing
operation of an auto-darkening lens control that has a detector and
associated circuitry to detect initiation of welding substantially
independently of time based filtering and to maintain detecting of
welding using time based discrimination, comprising coupling control
signals and power to an auto-darkening lens via a substantially unimpeded
path from a detector to the auto-darkening lens.