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Old September 9th, 2008, 08:25 AM   #91
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You're very right about false advertising -but what's the point really? Truth in advertising or a light that's better balanced than the advertised rating?
What I can't tolerate is lights that are BLUER or More CYAN than they're advertised to be.
I spent too much time in LED research, testing and evaluation. I finally settled on filtered Seoul P7 clusters such as the Lupine Betty-X.
I also still use filtered hotlights which are inefficient but effective.


Quote:
Originally Posted by Matt Gottshalk View Post
Yes I realize that. I also realize that true daylight is usually around 5600k, not counting for twilight or early morning hours.

Otherwise HMIs would be 4300k, wouldn't they?

Also, if a light is ADVERTISED as a 5600k light, then 4300k just does not cut it.
Period.
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Old September 9th, 2008, 08:38 AM   #92
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Surely what matters is how clean a white shows up on footage? For the eye to perceive a clean white, all that's needed is 5,000ēK on the nose on a white card. That assumes that you have a perfect sensor and signal processing in the CMOS.
"Most images that involve flesh tones, particularly of Caucasian persons will actually look pallid if lit with anything colder than 4,800ēK"
That's the sweet spot for Caucasian skin assuming an average background balance. If you're shooting reproduction of art or any still life that's color separation critical, then yes, 5,000ēK-5,600ēK is the sweet spot there.
LEDs are VERY different in how they interact with objects. It's the narrow band. It's not very 'real' when you consider the complexity of a stream of daylight interacting with all manner of surfaces. I'm designing an LED fixture that mimics full spectrum lights but delivers an aggregate of 5,000ēK. It should make objects look more natural - as though shot with daylight (To me, daylight is the combination of a massive diffuse skylight (generally 6,000ēK) pierced by source point , the sun-delivering between (4,000 and 5,000ēK) A soft bank of LED lights just mimics the skylight alone.

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Originally Posted by Richard Andrewski View Post
Most people believe and the consensus seems to be that daylight is between 5000K and 6500K so that's probably why they were concerned.
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Old September 9th, 2008, 08:42 AM   #93
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Ah! Yes. Production issues like hobbling presets can be a problem. My solution is to hand filter my LED lights to match my Incans with FULL CTB filters. That takes care of shifts. In fact, for what it's worth, I do the crazy thing of hand tinting my LED emitters with two sharpies to essentially alter their balance with out having to use gels.
OK, you read that here first ;)


Quote:
Originally Posted by Brian Standing View Post
Well, not only that, but there's the issue of trying to color-match to other artificial lights as well. If they're "daylight" balanced, they'll likely be in the 5500-5600K range. My tungsten lights with a dichroic filter come in right at 5600K, and right at 3200K without the filter. Part of the reason I want color-balanced lights, is so I can use 5600K presets in the camera and avoid the compromises of manual white balance.

Also, I can't speak for the light in Maryland, but in Wisconsin on most sunny days, my camera's white balance is showing between 5000K and 6500K. It only dips down to the 4000 range when the sun is low in the sky in the morning or at dusk.

That's interesting about the difficulties in measuring the color temperature of LED lights. Once I get my copy of DVRack working again, I'll have to light a scene with the LED 500 and look at it on the vector scope. I'll be picking up some minus-green gel tonight, so I guess further experimentation is in order.
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Old September 12th, 2008, 07:52 PM   #94
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Took a look on ebay at some so-called DJ lighting made by Chauvet (LED Techno Strobe ST-3000) panel and Chauvet (LED Rain 36) spot light. Could be useful. Hanging could be a little awkward. More like theatre lighting. Anyone try these...

Chauvet LED Rain 36 White DJ Lights Effect - eBay (item 380056771884 end time Sep-18-08 09:53:14 PDT)

NEW CHAUVET ST-3000LED DMX LED TECHNO STROBE LIGHT 3 ch - eBay (item 280264460865 end time Sep-16-08 18:48:28 PDT)

kj
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Old September 12th, 2008, 08:18 PM   #95
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Second item is actually a strobe (but looks like it can also be used as steady light.)

Careful with LED strobes - looks like they produce worst artifacts in EX1 and similar CMOS cameras:

http://www.dvinfo.net/conf/933029-post13.html
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Old September 13th, 2008, 01:04 PM   #96
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The second light, the panel led can be opeated in static mode.

NEW CHAUVET ST-3000LED DMX LED TECHNO STROBE LIGHT 3 ch - eBay (item 280264460865 end time Sep-16-08 18:48:28 PDT)

From some of the detail shots it looks to be really well made. Looks like you would need ac power cords. Anyone have an idea how they could be attached to a typical video light stand? I have a vast collection of Lowell Tota Stands. Could probably recycle the Lowell power cords as well.

kj
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Old September 13th, 2008, 01:14 PM   #97
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Here's a PDF of the users manual...

http://www.chauvetlighting.com/syste...3000LED_UG.pdf

kj
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Old September 13th, 2008, 01:28 PM   #98
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Here's the PDF for the Spot Light...
http://www.chauvetlighting.com/syste...-RAIN36_UG.pdf

kj
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Old September 13th, 2008, 06:07 PM   #99
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The unit has a yoke and a hole in the yoke so it should attach just like any other light with a baby stand to yoke adapter (also known as TVMP adapter).

I'm curious though why that one would be better than the 225 LED one on Ebay that started this thread. The price is quite different too but will it really be that much better for the price difference and it doesn't even have the same number of LEDs on it.
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Old September 14th, 2008, 01:34 PM   #100
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Thanks for the tip.
Quick search found a couple of TVMP adaptors...


Matthews | TVMP Adapter | 429492 | B&H Photo Video

Avenger E390 - TVMP ADAPTER(YOKE TO STAND)

Looks like it would be difficult/impossible to tilt the lights in a downward position. If you wanted to raise the light above a talent and have it shine down may be problematic.

kj
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Old September 14th, 2008, 06:00 PM   #101
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Yes, with a yoke like that, its really made more as a "grid" or ceiling type fixture. You really need a yoke that extends down from the sides and a fair ways below the fixture to use properly and get all the angles you might want.
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Old October 17th, 2008, 07:51 PM   #102
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Cool Lights LED 600

So we're getting closer on our LED Panel which is in production right now. The CL-LED600 should be out in early December if none of our other products hold it's availability up since a bunch are coming at the same time.

600 LEDs, 9 5/8" x 5/8" x 2 3/8" size. About 3 1/2 pounds weight (or so). Removable barndoors that slide out of an accessory holder. Angle adjustment stand adapter. Black powder coated aluminum construction. 12VDC power supply included: approximately 50w draw at 12VDC. Power input is via 4 pin XLR. Power supply includes a 6 foot cable from power supply to LED fixture and a 15 foot IEC type cord to power supply which has a carabiner on it to clip to some part of a stand rather than leaving it on the floor. Also includes a dimmer pot and bank select switches on the back. It will have two accessories as of right now that can also go on the back of the unit: either an AB Battery mount or a V Battery mount that can go on the back--customer installable. You can either get our battery mounts or probably use other ones too but I haven't tested any others than ours. The pricing for this panel will normally be $479 and $125 for the AB Mount accessory, $125 for the V Mount accessory. For a limited time, we'll be running a special for $379 for the panel and $99 for the battery mounts. As if all this wasn't enough, there is also a free padded nylon carrying case very similar to a laptop type bag but custom made for this panel. The size of the carrying case is 12" x 14" x 5 1/2". Pictures below.

Available in daylight (5600K) and a limited number of tungsten color units (3200K) available as well. Thanks for looking.
Attached Thumbnails
LED Lights-clled600cm.jpg   LED Lights-led600casecm.jpg  

LED Lights-vmountcm.jpg   LED Lights-abmountcm.jpg  

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Old October 17th, 2008, 10:19 PM   #103
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Quote:
Originally Posted by Richard Andrewski View Post
So we're getting closer on our LED Panel which is in production right now. The CL-LED600 should be out in early December if none of our other products hold it's availability up since a bunch are coming at the same time.

600 LEDs, 9 5/8" x 5/8" x 2 3/8" size. About 3 1/2 pounds weight (or so). Removable barndoors that slide out of an accessory holder. Angle adjustment stand adapter. Black powder coated aluminum construction. 12VDC power supply included: approximately 50w draw at 12VDC. Power input is via 4 pin XLR. Power supply includes a 6 foot cable from power supply to LED fixture and a 15 foot IEC type cord to power supply which has a carabiner on it to clip to some part of a stand rather than leaving it on the floor. Also includes a dimmer pot and bank select switches on the back. It will have two accessories as of right now that can also go on the back of the unit: either an AB Battery mount or a V Battery mount that can go on the back--customer installable. You can either get our battery mounts or probably use other ones too but I haven't tested any others than ours. The pricing for this panel will normally be $479 and $125 for the AB Mount accessory, $125 for the V Mount accessory. For a limited time, we'll be running a special for $379 for the panel and $99 for the battery mounts. As if all this wasn't enough, there is also a free padded nylon carrying case very similar to a laptop type bag but custom made for this panel. The size of the carrying case is 12" x 14" x 5 1/2". Pictures below.

Available in daylight (5600K) and a limited number of tungsten color units (3200K) available as well. Thanks for looking.
Hi Richard:

This looks very interesting. Do you have CRI and photometrics?

I may buy a few of these from you.

Thanks,

Dan
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Old October 18th, 2008, 08:54 AM   #104
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Thanks Dan. As for light meter readings, I'll take some next week and post as I need to get my meter which is in another city. CRI will be around 80 to 85 based on the LEDs we're using which is about as good as you can get for affordable 5mm and daylight white at this time. Ironically, you can find tungsten 5mm LEDs with better CRI but most people want daylight so that's what we needed to get.

CRI of 5mm LEDs depends upon a couple of factors from what I can tell--beam angle and color temperature influence the CRI you can have quite a bit. We started this project wanting to find a 20 to 30 degree beam LED so you'd have an instrument with super throw--really concentrated but a relatively small beam. One after another though, they all looked terrible. You'd get a halo around the beam that had a green or yellow tinge to it. The only way to minimize that effect if you wanted to use that beam angle was to go to 8000K to 9000K LEDs. The efficiency goes up in that range too and you get more lumen output.

While it may make a lot of sense, I didn't want to spend all my time explaining to people why I wasn't using 5600K ones so we skipped using those and went to a 60 degree LED. Less throw, but you can use 5600K LEDs and not have the halo and the beam is wider anyway so you can cover a larger area with the fixture. When I make a future on-camera smaller panel though we may have a 8000K version on that because it can make sense to have a sharp beam that can cut through things really well and be as efficient as possible for a small light.
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Old October 18th, 2008, 10:33 AM   #105
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Richard.... I'll take 4!

also... have you ever considered a fresnelish plastic sheet that would slide in front of the panel to focus the beam narrower? I picked up a sheet at officemax that is meant for overhead projectors. Also have one that is meant to be stuck on the rear window of a rv or van to give a wide view of behind the vehicle... this one widens the beam. These sheets are only about $10! and can be cut down to size. They appear to be very color neutral.

Keep up the good work! Your 150 daylight Fresnel's have been a fantastic addition to my kit!
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