chaikwa, thanks very much for your post, you make a good point. In getting the auto-darkening helmet i was hoping to eliminate the flashes that i get from my current helmet. I don't get the lens down in time or flip it up too soon. A relative told me that the first "cheap" one that he tried did not darken fast enough and he could see it. He replaced it. I am an occasional welder so I think I might be ok with a cheap one. I'll try to look into the studies.