ZebraLight H502 XM-L

[pjandyho]

lampDepeche,

This is what I have to say regarding the GITD and the green tint on the edge of the beam. You may have misunderstood and thought that the green tint could only come about through the emitted glow of the GITD, but that is where you may have gotten it wrong. Basically it is highly possible that the green is reflected off the GITD when the light is turned on. The difference here being reflected by and not emitted by the GITD. When reflection is concerned, the stronger the light source the stronger the reflected color would be. In this case, the GITD is green and so it reflects green onto the beam. Is that starting to sound logical to you?

I am not the expert here, but in photography I know that if I bounce my flash off a colored board I get exactly the color of light on my subject. Even though the GITD is not a reflector, it is inevitable that some light would spill over and get reflected off it.

And by the way, I don't see any green ring on any of my XM-L lights. And the Preon P0 which happens to have a GITD on it does produce a green ring on the outer edge of the beam, and it is not an XM-L in there.

 

[moozooh]

Nope, there is flaw in that logic. The light would have been reflected green if the reflector's surface was green, but by itself it's white. If you point a flashlight at your mobile phone, you won't magically have the phone screen's contents in the reflection.

I suppose you could fully check that by shining a very bright beam through some thin GitD-covered surface (one of those headstraps?) onto a white sheet to see if the penetrating beam had been tinted in any way. I bet it won't be.

 

[psychbeat]

Too Bad they didn't use orange GITD

Green tint is useable outside but can be unpleasant indoors....
To many of us Im sure some like it.

 

[varuscelli]

If I take an H600 and shine it through one of the GITD holders, the entire beam gets a greenish tint.

If I take a couple of loose GITD holders and wrap them together in a loop around the outer rim of the H600 lens in such a way that the H600 shines through the loop formed by the GITD holders, I can see a greenish tinge around the outer edges of the beam that looks very similar to what I see around the outer edges of the H502 beam.

I agree with pjandyho in this.

It looks to me as though the GITD coating on the reflector of the H502 could easily be causing the greenish tint on the outer edges of the H502 beam.

I'm not making a statement of fact about this, but the visual evidence I see seems to point to that as a logical conclusion.

Edit: These are pretty rough photos of a very roughly executed experiment (H600 shined through two GITD holders), and the color rendition might easily vary from monitor to monitor, but with my eyes viewing in person I see a greenish tint around the edges of the beam. I don't know how well others viewing this on their own monitors will see it, but there's a definite greenish tint around the outer edges of the beam (more exaggerated in size but very similar to what's seen with the H502.

I can very easily envision the light from the H502 emitter taking on such a tint around its edges based on the H502 GITD reflector.

 

[Mumbojumboo]

I like the glow. (MY wife said, "How do turn this thing off?" Me, " Ah, Yeah, it is off." I like the 120 degree spill. It fills in all the gaps left by my other lights.


mumbo glow by mumbojumboo, on Flickr

 

[moozooh]

If I take an H600 and shine it through one of the GITD holders, the entire beam gets a greenish tint.

If I take a couple of loose GITD holders and wrap them together in a loop around the outer rim of the H600 lens in such a way that the H600 shines through the loop formed by the GITD holders, I can see a greenish tinge around the outer edges of the beam that looks very similar to what I see around the outer edges of the H502 beam.

If that is the case, it seems that the coloration is caused by portions of the light going through the GitD reflector, reflecting from the underlying surface, and passing the GitD surface on its way back again, mixing in with the flow. In which case the possible solution would be to either make the back side of the reflector or the underlying surface light-absorbent so that the light that penetrates the GitD material doesn't return into the main flow.

 

[tickled]

If that is the case, it seems that the coloration is caused by portions of the light going through the GitD reflector, reflecting from the underlying surface, and passing the GitD surface on its way back again, mixing in with the flow. In which case the possible solution would be to either make the back side of the reflector or the underlying surface light-absorbent so that the light that penetrates the GitD material doesn't return into the main flow.

I think it can be more simple than that.

 

[moozooh]

Yeah, by taking out the reflector, but then you'd lose the GitD feature. Or did you have anything else in mind?

 

[pjandyho]

Nope, there is flaw in that logic. The light would have been reflected green if the reflector's surface was green, but by itself it's white. If you point a flashlight at your mobile phone, you won't magically have the phone screen's contents in the reflection.

I suppose you could fully check that by shining a very bright beam through some thin GitD-covered surface (one of those headstraps?) onto a white sheet to see if the penetrating beam had been tinted in any way. I bet it won't be.

The reason why you don't see green in the entire beam profile is because the main beam which is still cool white is being projected by the domed optic on the LED unit itself. Maybe a small 20% or so of stray light from the main beam got reflected by the GITD, not strong enough to overpower the main beam, but enough to spill onto the edges of the main beam as the light start to fall off. Am I sounding logical enough?

 

[tickled]

Yeah, by taking out the reflector, but then you'd lose the GitD feature. Or did you have anything else in mind?

The glow in the dark material doesn't have to surround the emitter. I'm sure you've seen the glow in the dark o-rings that some people have added to their lights.

Personally after buying a light with these things built in, I find it adds nothing of value for me and would rather have an option to not have it. Even more so after seeing the drawback on this design. Worrying about a tint lottery is already bad enough!

 

[pjandyho]

The glow in the dark material doesn't have to surround the emitter. I'm sure you've seen the glow in the dark o-rings that some people have added to their lights.

Personally after buying a light with these things built in, I find it adds nothing of value for me and would rather have an option to not have it. Even more so after seeing the drawback on this design. Worrying about a tint lottery is already bad enough!

Agreed. I think the GITD in the H502 is so lame. Give me tritium slots.

 

[varuscelli]

I still have to note that given the broad beam of the H502, the greenish fringe has little to no effect on actual use of the lamp. For white wall hunting, yes -- you'll see it. In actual use I seriously doubt it should bother anyone. I think most of the time for most uses, the eyes will be looking more toward the central to mid portions of the beam.

And I still wonder if the GITD coating serves a functional purpose beyond GITD. Perhaps as ZebraLight was experimenting with variations they found that in conjunction with the reflector the GITD coating helped to diffuse the beam, so they achieved multiple levels of functionality with the coating. Just hazarding a guess.

 

[srfreddy]

The emmision angle of the XML isn't huge.... only 125 degrees. So the outer 2.5 degrees of the light are hitting the bezel and the GITD. People have said that there is a faint hotspot, so the GITD is probably reflecting white light forwards...

 

[varuscelli]

The emmision angle of the XML isn't huge.... only 125 degrees. So the outer 2.5 degrees of the light are hitting the bezel and the GITD. People have said that there is a faint hotspot, so the GITD is probably reflecting white light forwards...

And perhaps the reflection off the bezel itself (from the GITD coating) is responsible for the part of greenish fringe on the beam.

It'll be interesting to see what people say about the c, d, and w versions of the H502 in terms of the GITD coating perhaps having an effect on those beams. I wonder if the effect would be more pronounced with the cooler tint lights with the initially released H502 perhaps showing the worst effect...but this is far from my area of expertise. And I realize there are other factors involved (different emitters, different color temperatures, etc.)

Interestingly, if I take my old H501w and shine it through a GITD holder (with the holder completely masking the front of the light) I see no hint of green at all on a white wall. The beam from the H600 showed an obvious green tint when the same thing was done.

 

[YoSeKi]

The emmision angle of the XML isn't huge.... only 125 degrees. So the outer 2.5 degrees of the light are hitting the bezel and the GITD. People have said that there is a faint hotspot, so the GITD is probably reflecting white light forwards...

The full emission angle is probably closer to 160-170 degrees. 125 degrees is the viewing angle full width half maximum (FWHM), or the off axis angle where lux is at least one half of the maximum.

The XML should be twice as bright at center as it is at 125 degrees. That is enough to create a faint hotspot up close with or without the GITD reflector.

 

[YoSeKi]

And perhaps the reflection off the bezel itself (from the GITD coating) is responsible for the part of greenish fringe on the beam.

Every cool white XML that I have seen produced a yellow to green fringe regardless of reflector material. I do not know if the GITD coating contributes to the green fringe, but I think the fringe would be there regardless.

I copied the photo below from another thread. It shows a bare XML without any kind of reflector. The green fringe is prominent.

 

[hemdale]

Re: ZebraLight H502 X-ML

Hi guys,

So does the H502 has a more cool or neutral tint ? I'd like to avoid "too" cold or greenish / blueish tints.
Many thks

 

[Bolster]

Re: ZebraLight H502 X-ML

Question: to the extent the "reflector" (I think it's more of a 'backdrop,' really) on the H502 is casting a tint, wouldn't it be casting that tint forward to the center of the beam? I'd think light at the edges of the beam would originate directly from the emitter, not arrive at the edge of the beam by bouncing off the "reflector"-- that would concentrate light forward.

Yet we're not hearing the center of the beam has a greenish tint. I'd suspect the emitter itself for a fringe of green tint, not the "reflector" (backdrop).

 

[moozooh]

Re: ZebraLight H502 X-ML

My guess would be that only the rim area of the overall light cone emitted from the LED comes in contact with the reflector in the first place, so the small tinted bits that are lucky to get bounced towards the center are completely washed out by the pure light.

 

[lampeDépêche]

You may have misunderstood and thought that the green tint could only come about through the emitted glow of the GITD, but that is where you may have gotten it wrong. Basically it is highly possible that the green is reflected off the GITD when the light is turned on.

Thanks, pjandyho! I think I understand better now the hypothesis that is being put forward.

Smarter people than me will have to see whether it is confirmed or rejected!

But I'm grateful to you for your patience in helping me see what was being proposed.