Equipment - electronic "dot" sight. Using a firearm "red dot sight" to help with long-zoom photos, for instance helping keep a flying bird centered when you are at full zoom. I know my 100-400mm lens is tough with things that are moving so this would be great. And keep in mind this is not a "laser sight", this has a little piece of glass on the end, the red dot is projected on that, like a HUD (heads-up-display) so nothing is projected out past the end of the sight itself.