Sandia Labs worked with the military to develop a different method to change focal length of a scope. They used the human eye for inspiration.
They call it Rapid Adaptive Zoom for Assault Rifles. According to Popular Science:
RAZAR does this using minimal energy, with 10,000 focus changes burning through only two AA batteries. After the batteries are dead, the lens can’t adjust until new ones are put in. But unlike systems that use electronic cameras for zooming, the lens still works without power.
It shall be interesting to see this technology used for commercial applications. In the meantime, I will just keep using my switchview lever to rapidly adjust my zoom levels. I could also simply leave my scope at a given mangification and put an angled sight on my weapon and zero it for close range targets. So rather than having to adjust my zoom and take my hands off the weapon, like the video above mentions, I just rotate my weapon to my secondary sight system and engage targets. Smooth, requires no batteries and is a lot cheaper.