OK, played a bit with the new 'bullet' IR and it's nice.
http://www.aliexpress.com/item/Surv...ray-3800mW-Light-15-90m-Angle/1875583826.html
(i ordered mine when it was on sale for~$50. seen similar ones listed, but chose this one as it claims 4500mw output
while the others were 3800mw or less. might just be spec-drift, but maybe not...)
turns out it DOES have a little photosensor on the barrel to turn itself on at night.
(that little green dot behind the lens adjustment knob).
the knob works by pulling it out and then turning to adjust beam spread.
then push it back in to lock in place, kinda like a watch dial that way.
the beam is very focused, with very rapid light dropoff at the edges.
this is GOOD for focusing the light where you need it at distance,
like for a license plate cam.
Even at widest spread, the light dropoff is very signifcant around the edges.
no gradual smooth transition like with these other units (see below), so unless
you adjust it to spread wider than your cam view, you get a hot spot.
it does seem to be pretty even across the beam, at least, but i haven't
examined that real closely yet.
I also have one of these (claimed 15 degree version):
http://s.click.aliexpress.com/e/chDhxKxW
This does work, and given the format (many small LED's) the beam has much more gradual fadeout around the edges than the unit above.
here's a view without and with the 15 degree 20w multi-led unit. note how it does provide more IR out where
one of my licence-plate cams is aimed (~60ft):


i got it thinking i needed more IR to get plates out there, but it turns out i have a focus issue
with the 25mm hik bullet conversion. need to open that up again and re-focus...
must make my house look like a crack-house or something tho, as I've had at least couple unsavory-looking types come up on the front porch
to try and look in thru the front door after apparently noticing the red glow. one guy even rang the doorbell at 5am in the morning and
gave my wife and myself a bit of a scare as we watched him tried the door handles. wtf?...
will try to post some comparison shots of the focused bullet IR some evening when i have a chance.