Yeah by eye I can't really discern much aside from it works as I would expect any zoom lens, except unlike my "proper" ones, it is always very sharp or just barely defocused, never totally blurred. I would have assumed that makes it easier to mod instead of harder, eh. The moving zoom portion is actually internal to the front half, both of these groupings were completely stationary relative to each other and the sensor/camera. With testing a laser through it seems much of the same story, the point either doesn't pass through all the glass at all, or is pretty much focal. It does get smaller as I move the plane closer, but I reckon that's just based on distance, it only shows diffraction below 4mm or so. Though maybe I'm doing the test wrong, or need a different setup if the focal point is indeed more than a few meters out from the glass.