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Thread: Strobes: Xenon vs LED

  1. #31
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    Flash leds are often on ceramic slabs. One choosen for very good thermal conductivity.

    Tests in pulsing Luxeons, up to Luxeon III or IV showed that they were fast, a turn-on time about ~100 nS, but brightness was not significantly enhanced. I used to design for a LED flashlight company. I had access to Nichia and Luxeon of a very good binning.

    I've seen the enhancement pulsing in car tail lights/police lighting, and it can be annoying if you shift your head really, really fast. Also shows up in some led aviation warning beacons.

    I note the Whelen's of the world are only just now emulating short xenon pulses in white led, somewhat effectively.

    Steve

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    Quote Originally Posted by mixedgas View Post
    I've seen the enhancement pulsing in car tail lights/police lighting, and it can be annoying if you shift your head really, really fast. Also shows up in some led aviation warning beacons.

    Steve
    Very annoying in traffic when checking blind spots and other such quick head movements. At night, you can really see it... the staccato POV is very apparent.
    If you're the smartest person in the room, then you're in the wrong room.

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    Resurrected this thread as I was wondering if anyone was using these:

    http://www.thomann.de/gb/american_dj_freq_16_strobe.htm

    Look pretty darn good and come in 5 and 16 led varieties with DMX, remote control, pre-set chases, sound to light and power and DMX pass through:



    Freq 5 in a full set up from a French DJ (not sure about his laser set up then again this is about the strobe):


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    Quote Originally Posted by absolom7691 View Post
    Very annoying in traffic when checking blind spots and other such quick head movements. At night, you can really see it... the staccato POV is very apparent.
    I wanted to do that as a DIY bike light several years ago and was told that it was not compliant with regulations, was unsafe, etc. Probably all garbage, given what people do now.

    The way I saw it, it was a neat trick to get lower power to be less annoying, not more, to save power, get long life, etc. The one time it needed to be seen most was by a person moving too much to be attentive to a small bike in a large road, and the moment they were adapted to its presence and not moving erratically relative to it, it would fade more than a steady lamp would relative to other lights. The idea that it should dominate when it should, and not otherwise, was a good idea. I was intending to use 3.5 KHz, because it's only seen as a series of dots if you're moving way too fast to see a low-powered steady light properly. I've seen a lot more annoying lights on roads! Those HID lamps, all that blue... people seem to believe those will make them see better, but a lot less hard blue spectrum light would work wonders. Europeans knew this for decades, all those yellow headlights..

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    I hate HID headlights. Whenever a car with HIDs passes me, I look at the light signature that they throw on the road vs mine (halogen) and I cannot see how the visibility is better. It looks worse from where I am sitting. They boast a really high CRI but I don't see it. It is blue! I would guess about 6500K, maybe higher. I am sticking with halogens for as long as I can.
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    I felt a tiny bit guilty for gazumping White-light's reason to resurrect, but never mind, good discussion, never really gets old.

    I bought a Fenix PD32 flashlight last year, then when a newer special version was released I did it again largely because of the change in LED type and spectrum. It's well worth it, distant ground when running at night, needs to be seen clearly with grey and brown easily told apart because it can make a big difference to whether I gouge an instep or not. And the older ones were terrible in mist, never mind fog. The newer ones, as well as being more powerful, have a much stronger green-yellow bias to the spectrum that makes them a lot more like the 20W halogen I used to have when I had a bike. The problem with LED's is that most firms are still at the stage where every time a significantly new lamp design is released, they want to push the power, and the resulting bluish light is nasty, and it usually takes a while before people start demanding better light quality, rather than quantity, before they improve them. I tend to buy the specials while they last, because the next big new light will usually look nasty again and it may be some time before it's worth buying a better version of it! There's no doubt that LED's will get there and stay there, but it's still too much of a lottery right now.

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    I have a Fenix TK20 and got it for the same reasons. Super bright, great color rendering and near perfect spot. I would compare it to a MiniMag halogen except it is brighter. Fenix makes great flashlights.
    If you're the smartest person in the room, then you're in the wrong room.

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    Quote Originally Posted by absolom7691 View Post
    I hate HID headlights. Whenever a car with HIDs passes me, I look at the light signature that they throw on the road vs mine (halogen) and I cannot see how the visibility is better. It looks worse from where I am sitting. They boast a really high CRI but I don't see it. It is blue! I would guess about 6500K, maybe higher. I am sticking with halogens for as long as I can.
    OEM HID is typically @4,500K (around daylight)

    After market HID @ 6,500K.

    Styling HID anywhere between 6,500K - 12,000 depending on the desired tinted colour.

    However, the higher the colour temperature, the less light you get on the road plus in many jurisdictions, the higher temps aren't road legal.

    The main advantage of HID is the visibility. The colour is more natural being akin to daylight so you see better + its around 2.5 times as bright as halogen at OEM / after market levels. The downside of HID is that in urban environments, sodium street lights tend to cancel the light out so around town you have less light than with halogen. On the open road or suburban, you can see a lot lot better though.

    I used to have HID's fitted to one of my previous cars.

    PS I don't mind a thread divert for a while, its all interesting stuff and I'm pretty laid back generally.

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    Ok. And at the risk of looking like I'm on the wrong forum entirely I have a question, preceded by the reason for it...

    I set up solar power, purely because I always wanted to explore it and the efficiency that is needed for it to be cost effective. I got a powerful 50W LED floodlight and fit a dimmer of my own design, etc etc etc.. And because it's my main room light the colour really matters to me. And it's lousy, like a sickly early 70's fluorescent lamp at best. The seller was great, even made up a special hybrid phosphor mix for me, based on the two standards, 'warm white' and 'cool white'. The result is at least familiar to people used to older lighting, but it's still not good for colour rendering, and has a nasty pinkish purple aspect that no variety of sun-like stage gel filtering seems to fix. The array area is 7/8'' by 7/8'' and any replacement needs to match if I am to use the same reflector, but the mounting plate details can vary as there's no difficulty drilling and tapping the lamp's heatsink. As a guide to colour (I have no spectrograph, and vague subjective descriptions won't help) the best I can do is say that Fenix's old P3D 'premium' light with the Luxeon 'Rebel' RB100 LED is the best I have ever seen, and pretty much ideal for still photography where exposure time can make up for the limited light output, with the Fenix PD32 'Ultimate Edition' Cree XM-L (T6) neutral white at its brightest being an extremely close (but a tad bit greenish) second, beside either of which that floodlight is an unsettling ill pink. If I can get the right (halogen-like) colour at 50W, or even 100W, I want to do it.

    Having set it up that much, the question is easy: Where can I be sure of getting one?

  10. #40
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    one of the members here (csshih) has a business that specializes in high end LED flashlights. ping him. i'm sure he can connect you to the right source/information on LEDs with excellent color temperatures and anything else you might need to know.

    Quote Originally Posted by The_Doctor View Post
    Ok. And at the risk of looking like I'm on the wrong forum entirely I have a question, preceded by the reason for it...

    I set up solar power, purely because I always wanted to explore it and the efficiency that is needed for it to be cost effective. I got a powerful 50W LED floodlight and fit a dimmer of my own design, etc etc etc.. And because it's my main room light the colour really matters to me. And it's lousy, like a sickly early 70's fluorescent lamp at best. The seller was great, even made up a special hybrid phosphor mix for me, based on the two standards, 'warm white' and 'cool white'. The result is at least familiar to people used to older lighting, but it's still not good for colour rendering, and has a nasty pinkish purple aspect that no variety of sun-like stage gel filtering seems to fix. The array area is 7/8'' by 7/8'' and any replacement needs to match if I am to use the same reflector, but the mounting plate details can vary as there's no difficulty drilling and tapping the lamp's heatsink. As a guide to colour (I have no spectrograph, and vague subjective descriptions won't help) the best I can do is say that Fenix's old P3D 'premium' light with the Luxeon 'Rebel' RB100 LED is the best I have ever seen, and pretty much ideal for still photography where exposure time can make up for the limited light output, with the Fenix PD32 'Ultimate Edition' Cree XM-L (T6) neutral white at its brightest being an extremely close (but a tad bit greenish) second, beside either of which that floodlight is an unsettling ill pink. If I can get the right (halogen-like) colour at 50W, or even 100W, I want to do it.

    Having set it up that much, the question is easy: Where can I be sure of getting one?
    suppose you're thinkin' about a plate o' shrimp. Suddenly someone'll say, like, plate, or shrimp, or plate o' shrimp out of the blue, no explanation. No point in lookin' for one, either. It's all part of a cosmic unconciousness.

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