MK Controls sells The Lightening Bug -- I won one in a raffle last year but have not had a chance to try it out. The explanation below answers the question of how well it captures a strike ... it is triggered, according to their manual, by the preceding infrared light. Again, I have not used this ... just posting for the information!
The Lightning Bug™ is based upon the science of lightning. There are two
components of lightning; the bright white flash everyone wants to capture and
the unseen infrared light that always precedes it. The Lightning Bug™ uses a highspeed
photodiode sensor optimized to sense the infrared burst that occurs just
before a lightning strike. This infrared light comes from the vaporization of air and
particles in the air. The Lightning Bug™ acts as a lookout for your camera,
watching for a change in infrared light. When a significant change of infrared light
over a very short period of time is detected, it trips the camera shutter to capture
the visible lightning bolt.
The Lightning Bug™ can also be used to take photos of fireworks, cannon shots,
virtually anything that produces a fast-acting rise of infrared light formed by a
high-temperature event.