Light QUALITY versus quantity

[kramer5150]

We often hear about the "quality" of emitted light. The lights ability to reveal textures, penetrate through surface shadows and accurately render color. To some it's a kind of abstract entity. To put it into words, its like seeing through the leaves and twigs and seeing the bark or mossy texture of a tree trunk. Only my brightest LED lights really possess this ability… or so I thought.

The video below is a 1 minute portion of the beamshot review of my shiningbeam.com RC-N3-Q5. Look closely and you can see how superior quality this light is to the DX:6090 (Cree P4) at illuminating deeply into the small shrub. The RC-N3-Q5 lights through the shrub, past the leaves and sticks and projects light onto the window behind the shrub. You can see a small little reflection off the glass right in the center of the shrub, it looks like a bright dot right in the middle. Notice how when I toggle back and forth between the RC-N3 and 6090 that reflection comes and goes with the deeper-penetrating light. Notice how also the deeper penetrating light is NOT the most luminous. The 6090 clearly emits more lumens, yet is unable to project light THROUGH foliage like the RC-N3-Q5.

Pretty phenomenal, when you consider the RC-N3-Q5 was powered at 3V with a semi-used primary, and the DX6090 was being run at 8.4Volts with two RCR123 cells.

I had to go back outside and inspect the shrub and make sure there wasn't anything shiny or reflective in there... NADA, that bright spot you see in the vid is light reflcting off the window glass through the foliage.

FWIW, I held both lights right next to each other in the video. Tactical holds in each hand. The heels of my hands were pressed against each other, thumb clicking back and forth.

Heres the vid...
http://www.youtube.com/watch?v=_ztQVtsH9-w

 

[Marduke]

Re: Light QUALITY, Cree Q5, BELIEVE the HYPE!!

Um, the P4 and Q5 bins are the exact same model LED. There is absolutely no physical difference between them. Each bin can range widely with different tints. The flux bin is completely separate from the tint bin. You can just of easily had a Q5 which was colder, more blue than any other LED you own

 

[kramer5150]

Re: Light QUALITY, Cree Q5, BELIEVE the HYPE!!

Um, the P4 and Q5 bins are the exact same model LED. There is absolutely no physical difference between them. Each bin can range widely with different tints. The flux bin is completely separate from the tint bin. You can just of easily had a Q5 which was colder, more blue than any other LED you own

I guess I got lucky then with this particular Q5... Either way, I was pretty floored at the lower Lumen torch and its ability to shine light through the leaves better than the higher lumen torch.

I probably should go back and edit my post to clean up some of it.

**edit** OP edited, I should know better than to post sensationalistic thread topics

 

[WadeF]

Re: Light QUALITY, Cree Q5, BELIEVE the HYPE!!

Well, this is my analysis of the video...

The brighter light doesn't penetrate the bush, and neither does the dimmer one. What you are seeing is light from inside the house shinning out through the bush. If you had turned your lights off long enough to allow the exposure of the camera to adjust I have a feeling you'd see your "window reflection" with no flashlights on at all.

The brighter light causes the camera's exposure to adjust, making it so you can't see the faint light coming out from the window and through the bush, plus you have all that light on the bush that over powers the indoor light shining through.

When you switch the to dimmer light the camera's exposure adjust to become more sensative and it now picks up the light shining through the bush from inside the house. The light from the flashlight doesn't wash it out like the brighter light does.

There are a couple times in the video where you can see this "reflection" when your hot spot moves away from it, and the "reflection" doesn't change in intesity, meaning the light is coming from out of the window from behind the bush.

Edit: Okay, I watched again. At the very end you move the hot spot away, and the spot disappears... However you also throw in a dissolve about that time which makes it harder to tell what is going on.

What I think is going on now is you are getting a reflection off the glass, but the dimmer light allows the reflection to be visible. With the brighter light the reflection blends in, or is over powered by, the light reflecting off the leaves of the bush.

 

[kramer5150]

Re: Light QUALITY, Cree Q5, BELIEVE the HYPE!!

Well, this is my analysis of the video...

The brighter light doesn't penetrate the bush, and neither does the dimmer one. What you are seeing is light from inside the house shinning out through the bush. If you had turned your lights off long enough to allow the exposure of the camera to adjust I have a feeling you'd see your "window reflection" with no flashlights on at all.

The brighter light causes the camera's exposure to adjust, making it so you can't see the faint light coming out from the window and through the bush, plus you have all that light on the bush that over powers the indoor light shining through.

When you switch the to dimmer light the camera's exposure adjust to become more sensative and it now picks up the light shining through the bush from inside the house. The light from the flashlight doesn't wash it out like the brighter light does.

There are a couple times in the video where you can see this "reflection" when your hot spot moves away from it, and the "reflection" doesn't change in intesity, meaning the light is coming from out of the window from behind the bush.

I was thinking about that too. The thing that puzzles me is that my mini-DV camera doesn't auto-adjust THAT quickly. It needs a couple seconds at least to auto-equalize for the light intensities, thats one of the things that drive me nuts about it. Also, the house inside & window was completely dark at the time.

This reminds me of those ghost sighting videos:thumbsup:

????

 

[WadeF]

Re: Light QUALITY, Cree Q5, BELIEVE the HYPE!!

I think the easiest way to describe this is the brighter light reflecting off the leaves is over powering the reflection. Your eyes, or the camera at least, doesn't pick up on it. With the dimmer light the bush is darker, allowing you to see the reflection from the LED. What you see is the LED itself reflecting off the window. Shine your LED light 800 feet across a field. You may see nothing, but hit a mirror pointed back at you at 800 feet and you'll see the reflection. Now light up the area around the mirror with spot lights and see if you can still see your reflection.

I don't think there is any difference in penetration. It just has to do with the way your eyes, and the camera's exposure, is adjusting to the amount of light. Try walking through dense woods with a 1,000 lumen spot light. All you will see is the branches and leaves close to you and nothing much past them, because the light that is reflection off the surfaces that are close to you are so bright your eyes can't see the dimmer light past the close surfaces. Now use a dim light that doesn't close down your pupils and you will be able to see farther.

It doesn't mean the 1,000 lumen spot light wasn't penetrating better, it certainly was, but you just couldn't tell because your pupils were closed down so much.

 

[kramer5150]

Ooooh... OK that makes sense.

This goes to show how pictures, video and even your own two eyes can be deceiving.

 

[easilyled]

There are some high-CRI leds being made now by Nichia, Seoul, Cree etc.

McGizmo's SunDrop is using one, and Dereelight are offering a module
with high CRI-Cree in the Marketplace.

If you're interested there are many threads in the McGizmo forum about
this topic (since it seems relevant to this thread).