David,
By chopped, I meant reducing the OD down to Larry's target diameter; a removal of the front end. The 19 mm has a much shorter focal length than the 20 mm so even at reduced diameters, you still have a reasonably deep and effective reflector. With the Luxeon's, the 19 can be stood off up to .060" to tighten and sharpen the projection of the beam. The light loss from backing the LED away from the reflector is more than made up for by the gain in the more intense rays which are then being redirected by the reflector.
************
I have a modded Mag AA that hosts a McR-19 and when you first turn it on, you have a good flood beam. As you adjust the reflector further away from the LED, you can see light from the corona fan into a spot that provides more reach (throw) of the beam. Unlike the stock light with the incan, this adjustment from flood to spot is artifact and donut free.
The McR-18 are currently in very short supply but I have a large order in process. Its versatility in retrofit was not fully appreciated or explored and although the shoppe started out with a fair number of reflectors there were apparently a couple orders in quantities that essentially cleaned the inventory out. I have a few more I held back in personal reserve that I will get to Wayne and Cindy and perhaps the members here can go light on the quantities ordered to spread the access for experimentation until the shelves get filled once again.
For any given focal length of a parabolic or psuedo parabolic curve, as you increase the depth of the reflector by providing more reflective surface further away from the focal pont or LED, you increase the percentage of light output that is managed by and redirected by the reflector. Due to imperfections in the reflective surface (orange peel) as well as a non infinitely small point source of light (image) and deviations in the curve as well as focal allignment, a deeper reflector of the same focal length can be seen to concentrate both the spot and corona portions of the beem into smaller angles of distribution with higher intensities of light within. To my vision, more significant and noticible at a glance than the increase of the throw of the spot is the increase in effective range of the corona.
The 19, 27L and 45 mm reflectors are examples of this. It is beyond the spot where the strength of these reflectors can be seen, IMHO. The trade off is of course in real estate and flashlight size required to support the deeper reflectors. Both the corona and spot portions of a projected LED have a field of view and range in which they are viable for illumination. Variations in the depth of reflector used, of the same focal length, will act on both the throw as well as the field of view for both spot and corona but not to the same magnitude. With a perfectly smooth and alligned reflector acting on a relatively small image or source, increasing the depth of the reflector would increase the intensity of the spot with little change in its field of view. This increase would have little effect on the intensity of the corona but it would reduce its field of view as the exit angle of direct (non reflected) light is reduced. With orange peel, on the surface, the reflected beam is more divergent and some light is out of column and added to the corona. Increasing the depth of an orange peeled reflector Reduces the apparent field of view of the spot, reduces tha actual field of view of the corona and increases the intensity of light in both portions of the beam. Of significance, at least to me, increasing the depth of an orange peeled reflector also blurs the transition edge in the portion of the beam where you go from the spot into the corona region. The contrast of light in the overall beam is reduced by a deeper orange peeled reflector.
By chopped, I meant reducing the OD down to Larry's target diameter; a removal of the front end. The 19 mm has a much shorter focal length than the 20 mm so even at reduced diameters, you still have a reasonably deep and effective reflector. With the Luxeon's, the 19 can be stood off up to .060" to tighten and sharpen the projection of the beam. The light loss from backing the LED away from the reflector is more than made up for by the gain in the more intense rays which are then being redirected by the reflector.
************
I have a modded Mag AA that hosts a McR-19 and when you first turn it on, you have a good flood beam. As you adjust the reflector further away from the LED, you can see light from the corona fan into a spot that provides more reach (throw) of the beam. Unlike the stock light with the incan, this adjustment from flood to spot is artifact and donut free.
The McR-18 are currently in very short supply but I have a large order in process. Its versatility in retrofit was not fully appreciated or explored and although the shoppe started out with a fair number of reflectors there were apparently a couple orders in quantities that essentially cleaned the inventory out. I have a few more I held back in personal reserve that I will get to Wayne and Cindy and perhaps the members here can go light on the quantities ordered to spread the access for experimentation until the shelves get filled once again.
For any given focal length of a parabolic or psuedo parabolic curve, as you increase the depth of the reflector by providing more reflective surface further away from the focal pont or LED, you increase the percentage of light output that is managed by and redirected by the reflector. Due to imperfections in the reflective surface (orange peel) as well as a non infinitely small point source of light (image) and deviations in the curve as well as focal allignment, a deeper reflector of the same focal length can be seen to concentrate both the spot and corona portions of the beem into smaller angles of distribution with higher intensities of light within. To my vision, more significant and noticible at a glance than the increase of the throw of the spot is the increase in effective range of the corona.
The 19, 27L and 45 mm reflectors are examples of this. It is beyond the spot where the strength of these reflectors can be seen, IMHO. The trade off is of course in real estate and flashlight size required to support the deeper reflectors. Both the corona and spot portions of a projected LED have a field of view and range in which they are viable for illumination. Variations in the depth of reflector used, of the same focal length, will act on both the throw as well as the field of view for both spot and corona but not to the same magnitude. With a perfectly smooth and alligned reflector acting on a relatively small image or source, increasing the depth of the reflector would increase the intensity of the spot with little change in its field of view. This increase would have little effect on the intensity of the corona but it would reduce its field of view as the exit angle of direct (non reflected) light is reduced. With orange peel, on the surface, the reflected beam is more divergent and some light is out of column and added to the corona. Increasing the depth of an orange peeled reflector Reduces the apparent field of view of the spot, reduces tha actual field of view of the corona and increases the intensity of light in both portions of the beam. Of significance, at least to me, increasing the depth of an orange peeled reflector also blurs the transition edge in the portion of the beam where you go from the spot into the corona region. The contrast of light in the overall beam is reduced by a deeper orange peeled reflector.
Haste makes waste and I just grabbed parts out of an "optics" box to get the photo done. 
Wow, if I ever had the need for a UV light...
