djozz
(djozz)
127
Without owning a Z1 I think this is what happens:
The collar needs to match the lens to get an improvement. The Z1 lens has a short focal length and is quite close to the led, therefore the cone of light coming out of the collar does not fill out the whole surface of the Z1 lens, which in fact then behaves like a lens with smaller diameter and thus less throw: even if the collar is focussed well the gain is more than compensated by the effectively smaller lens.