I hear you Nick. The focus is important.
It is surprising how different the beam patterns are, even with renowned brands like the Osram and Phillip's bulbs, in the same reflector. It must be down to subtle differences in the focus, ie, the light source position, as you describe above.
I am assuming that, as with say the DIN specs of nuts and bolts, that there is a similar spec for "H4" bulbs, which would apply, not only to the connection and mounting type, but also the focus of the beam, or filament position.
You used to be able to count on the old British Kite mark, which was probably superseded by an EEC standard.. Soon probably to be irrelevant! I have no idea if the Chinese manufacturers adhere to any such specs or even if they are policed to any degree?
It's largely a case of caveat emptor when buying new generation bulbs on eBay, as I seem to do quite a lot! Luckily so far the results seem to be quite good.
It was probably issues with focus that has lead to the outlawing of HID conversions? I do worry that some LEDs will fall foul to the same criteria as the HIDs. I am not au fait with the regs regarding what light power is allowed, but I do know there are limits for this, hence why some bulbs are sold "not for road use".
I'm enjoying the learning involved in this project and I've certainly made massive improvements to my Monster's lights in the standard shell and rim. At least night riding is no longer a fearful experience, I think I nearly "enjoyed" the last ride..
