Adaptive Headlights

I'm not objecting to you disagreeing - merely objecting to you calling my opinion naive. Which suggests I haven't given it any thought or know nothing about lighting.

But the 'simple and cheap' arguments are often put forward in favour of points and carbs. And those who do simply ignore efficiency.

Again why? Many cars still have incandescent main beams. For signalling purposes if nothing else. No reason why they couldn't be incorporated into a main beam HID setup for just this reason.

The light output of any lamp can be increased or decreased. Saying you can already buy an 150 watt H7 incandescent but only a 35 watt HID is pretty meaningless in the scale of things. However, upping the wattage of an incandescent can often result in reflector or lens damage due to heat. And voltage drop in the wiring etc can also cause problems.

The reflector behind a incandescent lamp in say an indicator or tail light

- not a passive reflector needed for safety. Because ordinary incandescent bulbs have a near omnidirectional beam pattern, some form of crude reflector is needed to increase the efficiency. Not so with an LED type where the lens is built in.

LED technology has a long way to go - as with much else in lighting. But the sure thing is the tungsten filament bulb's days are numbered.

The colour temperature of daylight varies by the time of day and weather conditions as well as latitude.

The cost, complexity and lack of "instant on" make these non-starters in automotice use for anything other than specialized purposes. IMO to suggest all cars shpuld rely on HID sole; is naive. Nothing personal...

I don't know anybody that prefers carbs to injection but I do know a few folks that will not convert older cars to pointless systems. Maintenance is minimal and they point out if/when they fail you can pretty much fix them with a rock but if a pointless system fails, you're screwed. I'm neutral on this and just keep my cars original.

I think it's the lack of an "instant on" abaility.

Understood. In halogen fixtured that have the bulb base and reflector than can handle it you can ho pretty high. Not sure what's actually under debate here.

LED"s shoot light out in one direction and lighting regulations require signalling lamps be seen from more than one direction. It's an issue.

Perhaps, when LED's can do what incandescents too. But until then.

Hey I *hate* incandescents in the house and everythning is CFL here, but having tried LEDS in the dask and dome lights - they just don't work well at all.

Yeah, but all things being equal, on a clear day at noon light is bluer towards the poles. 5000K is given at the equator by several sources (GE, Horst & Kipper) and 6500-7500K is given in "norther climes" whcih ranges from Boston to Denmark.

As you say, that's your opinion. Of course it's wrong, but you are entitled to your opinion.

"Instant on", as you put it, is a non issue. There are many, many cars running with BiXenon setups that have no need for "instant on" headlamps. They use a mechanical mask to create the low beam which moves out of the way to provide main (high) beams.

Besides, instant on is a misnomer. Even halogens take a finite period of time to begin to cast light. Yes, that is shorter than the time to ignite an HID bulb, but who cares? When I engage the HID Xenon lights on my car (not a BMW) they are lit in less than 1/2 a second. Why would you need them to respond any faster than that?

The total quality of light is dramatically greater with HID and the power demand from the alternator is less. HID lamps can be manufactured that shed light of different wavelengths. 4300k is usually the absolute greatest light quantity, and decreasing in output both wavelength directions.

If your problem is that you don't think headlamps should have greater than 5000k color temps then say so. It's not an issue with the method of the light that you have, but rather the color.

I'm not sure what this has to do with "you turn the switch on and the road it lit up".

Uh yeah, a little.

Who'd have ever thought you need more than 640K ?

K is a measure of light color, not the amount of luminous flux; it's a qualitative, not quantitice measurement. HIDs do draw less power, significantly so. They do not put out more light than thr Cibie CSR's, which are halogen, in my 633.

The color is the worst problem. But as long as I can get more light for 1/4 the cost I see no point in HID lamps to say nothing of the fact it's easy to install or adapt good halogens, but retroftting HIDs to any car is simply a fantasy.

It's a great technology to be sure, but its young and has a way to go.

I thought your desire for "instant on" was in regard to switching on the high beams. If all you a talking about is being able to instantly turn on the low beams, well... I don't get it. Why do you need to do that? I usually turn my low beams on long before actual dark and if they took a minute or longer to turn on, it would be no big deal. But as I said, it only takes a small fraction of a second, so who cares.

Huh? 640K what?

I'm fully aware of that. What I'm saying is that the HID lamps that put out light at 4300k *also* happen to be the ones that put out the most candlepower for the same (35W) input.

There are maximum limits set by the DOT for candlepower over a range of dimensions. If the Cibie's really do put out more (which I seriously doubt) then they would be illegal here.

Your Cibie's don't fit in any modern cars. When was the last car made that takes 5.25" round headlamps. They are also only available for "wrong-hand drive" applications, as far as I can see. Comparing them to factory Xenon HIDs (in the US anyway) is kind of moot.

But my point was (is) the color doesn't *have* to be a problem. 4300k HID is not blue in the least. In fact, 4300k happens to be in the frequency range that the eye sees best. With lower or higher frequencies a correction factor has to be applied to the measured light quantity to determine the effective light power.

And I have yet to see a car manufacturer offer up any car with halogen lights that come anywhere close to the light output of the HIDs.

Sure, they can be improved going forward, and I'm sure they will. But they're already better than all the alternatives.

This site appears to provide some credible info on HID lamps along with some interesting 'prism tricks' employed by BMW and Audi that make their headlights appear blue from the side even though they are actually white (4100K). It seems clear from this site that the true high temperature 'blue light' systems only have 'bling bling' value as they provide less light and that the human eye is less able to see that light.

To the original poster with the night vision problem I would suggest that he work on the other end of the problem and get some night vison glasses. I have an emergent night vision problem and find these lenses help significantly, especially in the rain. They also have the added benefit of acting as BLUE BLOCKERS knocking down the intensity of the oncoming beams from the affluent but ignorant purchasers of the blue light systems who for some reason usually drive around with their high beams up.

Have you ever driven a car with HID lighting? You very soon don't notice the *slight* difference in colour temperature if you've got 4300k lamps.

No it's not. I've driven a car with a conversion and it was fine - although of course illegal in the UK. But then so are greater than 55 watt halogens for dips.

It's anything but young - the technology has been used in film etc lighting for many years.

Very few cars have HID main (high) beams. Mostly they add incandescent high beam while leaving on the HID dipped one - no different from many incandescent only types. But plenty of boy racer types replace standard incandescent bulbs with blue incandescent types for the reasons boy racers have - they're actually less efficient than standard ones. True HID lights as have been said needn't appear blue - except when warming up, and on the edges of a projector system which is caused by the lens and happens with incandescent types too.

Barring some radically new tehnology or suspension of the laws physics HID lamps are going to be beams only and rely on halogens until they warm up.

The point is just because you can't see why youd need lights to come on the instant the switch is turned on doesn't mean it isn't required.

Handy in one sense, but you really want a much more yellow bulb when it foggy, raining or snowing.

Can you show me?

Yeah they really do. Dan Stern has the numbers.

Moot for new cars certainly.

Yeah that's great but, a) the eye i smost sensitive to green, not white and b) you want yellow(ish), not bluish white in inclement weather.

The spec for lighting in Canada is "must be visible from 200 feet (or yards, I froget). There's no economic justification for benig able to see properly so you can't rely on manufacurors to spend to much time (or money) on this. Good lighting is nearly always an aftermarket thing.

Doesn't even fit in older cars. Hardly the best. And there's nothing wrnog with them a bit more sodium wouodn't fix :-)

Of course not. Under warm white fluorescent or 7500K daylight or even gro-lux your eyes gets used to it and seems "normal".

The complaints piling up at NHSTA about oncoming HID dazzle tell another story though, they're damn annoying. In Yurrup yo uhave to have leverlers just to address this problem which are not required here.

What kind of conversion?

HID lamps are indeed not new, but they are very much so in automotive applications which is what I was referring to. "white" HID lamps are reaonably new, previously only mercuty (very blue) and sodium (very yellow) were available.

I have much better than average night vision, which is why oncoming HID's hurt so much.

The LAST thing you want to do at night is wear any type of sunglasses that cut down on the amount of light that enters your eyes, blue or not.

They're actually very illegal. And really stupid; they emit less light than non-blue bulbs.

You really think a lamp with a colour temperature far removed from daylight is going to be used as a daylight substitute or fill in filming?

As will high powered filament lights of a similar output. HIDs are far more common than aftermarket filament bulbs of the same light output - most light fittings and wiring can't handle 150 watt bulbs.

I don't know the law in your country.

But said just that in the bit you snipped. ;-)

Uh, no. That's why I didn't say that. HID lamps have been in use as street lights for decades. Low and high pressure sodium are usually used because they have the longest life. How often you change the bulb is a big deal when they're way up there. Mercury is ususally used where the amount but not color of light is important. They spike madly in the blu end of the spectrum.

HQI/Halide lamps have been around for "only" abot 30 years and are more or less "white".

Yes and no. Of course any high powered bulb is going to melt a cheap base/socket. But again, the color of the light is an issue here. 160W bulbs by themeslves will get you some flashes from oncoming drivers even on lowbeam (and of course I'm talking H2's here). but, with a yellow capsule over the bulb, you (or at least I) didn't get that once.