Surefire also should be having a precise reflector in the Arc Series lights too..
Well yes, that should be expected considering the prices of those lights.
EDIT: some more information regarding the luminance:
Here is a German thread on these lights where the topic was also discussed.
I will use the Lemax/XeVision XV-LX70 as an example.
To calculate the luminance we need the luminous intensity (1,370,700cd), the area of the reflector, the reflectivity of the reflectors coating and the transmission rate of the lens.
The large opening of the reflector has a diameter of 100mm (see
here). The small opening has a diameter of around 15mm.
The area (as seen from the hotspot) is thus 7854mm^2 - 177mm^2 = 7677mm^2
I have not found any information regarding the coating used for these reflectors. The reflecitivty could be anywhere between 75 and 98%. I will assume 90% of standard aluminium coatings.
The lenses are not ar-coated and made of Borofloat so they can tolerate the heat. Borofloat has a transmission rate of 94%.
So now the luminance of the part of the arc that is in the focal point of the reflector can be calculated.
Luminance = luminous_intensity / (area_of_reflector * reflectivity_of_reflector* transmission_rate_of _lens) = 211cd/mm^2
This is a very high value for such an HID bulb.
Here one can find a detailed doctor thesis (in German) where the luminance of such bulbs was measured.
At 35W this would only be possible by focussing on one of the electrode tips. At 70W things are different though. It's possible that the center of the arc reaches 200cd/mm^2 since the bulbs are more than twice as bright at these power levels.
So my statement above is not valid anymore. I don't know how they focus these lights.