There’s an idea.

There are a number of cheap zoom flashlights that do not change external volume. To cycle the zoom the operator turns a ring that causes the pill with the star on it to go up and down inside the light. However, this does have some disadvantages:

  • Not at all airtight - there is a mechanical gearing system and ring that is completely exposed. Air and water can get inside around the ring.
  • Thermal management - the star sits on a little platform that moves up and down. This system has extremely poor transfer of heat to the outside of the light. The platform cannot be too tight against the sides of the light or the system will jam.
  • Wires - each time the platform moves up and down the driver wires compress or extend. I haven’t tested it, but that certainly doesn’t sound like a system that would last for the long-term. How long would it be before one of those wires or solder joints failed?
  • Size - The internal volume of the light must be big enough to accomodate flood mode with the gap between the lens and LED at the focal length of the lens. This makes for a big zoom light that cannot retract into a more compact and convenient size for pocket carry.

Many of these problems could potentially be fixed, but I don’t think anyone has tried yet. Maybe a magnetic system, extra o-rings around the ring, or a motor to operate the zoom to reduce openings to the outside. Maybe conductive tracks instead of bending wires for durability. Maybe make the platform entirely of copper to help out in heat conduction.

I remember watching a demonstration video about a product some company was developing 5 or 6 years ago that looked really cool. Unfortunately I didn’t make note of the company and have never heard of them again. I guess they failed.

The product was a flexible lens. In one configuration it operated like a flat window. But rotate the collar around it and it squeezed the lens into the shape of a functional aspheric. In the video they even used it on a demonstration flashlight showing how it could go from spot to flood with the only moving part being how the lens was squeezed. looked pretty neat. Too bad that didn’t take off. If it worked, just about every flashlight could be a zoomie.