DIY Light

[zagnut]

So, I've needed a fairly compact light for a while now. But my budget is extremely limited these days (whose isn't?).

Anyways, my mother bought me one of these recently because she thinks I'm depressed due to not getting enough sunlight -
http://www.amazon.com/Sphere-Gadget-.../dp/B004JF3G08

It's actually quite small at 6 x 6.5 x 1 (inches) and weighs next to nothing. It contains 72 LEDs. Company claims "10,000 LUX!". Meh. I was doubtful about the claim of 10k lux. Sooo....I fired up the incident meter on my cell phone and made sure it was calibrated to 0 in complete dark. About 12 inches in front of the light, it measured approximately 2,200 LUX. At exactly 6 feet, approximately 1,150 LUX. This thing is actually really bright. I can't stare directly at it, it hurts my eyes. It's got three settings, hi, medium and low. I only measured high. Now part of the reason it's so light (no pun intended) is because power is supplied by your common wall wart.

I found an online LUX to lumens converter. My measurements convert to 204 lm/ft2 at 1 foot and 107 lm/ft2 at 6 feet. It also has a nifty flip out stand that can be used instead of using a bracket to mount it to cam and/or tripod.

I'm thinking about painting it black, building a battery pack (requires 12v DC, 600ma (0.6A or 7.2W) and a bracket to mount it to the camera for when I need extra light. So, thanks for the new camera light mom! New toys always help to decrease depression...lol.

Oh, as for color temperature, I can't find it listed in spec sheet or online....yet. How can I measure it? These things are supposed to simulate natural daylight, but it would be nice to know what the temp is.

[cgbier]

You got lightroom or Aperture? Set your HV or HF or whatever to custom light balance and take a still in darkness with just this light on. Lightroom or Aperture will show your color temperature. Normally, these therapy lights are 6500K.

[cgbier]

A lightstand or camera bracket should easily built for that thing.
Battery brackets can be purchased from ext. monitor distributors.

[zagnut]

Thanks CG! I was thinking it'd be simple to build a bracket set up. Might be able to drill a hole in the bottom, open it up and epoxy a 1/4-20 nut behind that hole. Gotta wait till I got a few extra dollars for building a building a battery holder / setup. Hopefully this week.

As for the color temp, I'd want to use as close to white a background as possible, even though I'd adjust for custom WB, wouldn't I?

[cgbier]

You'll have to have some white stuff in the picture. Have a piece of Printer paper in the scene. That's not 100% white, but good enough.

[zagnut]

That's what I was thinking. Probably hang an old white bedsheet or use paper like you said.

[cgbier]

The bed sheet only works if it was washed in Clorox
But you are on to something: Laundry detergents contain blue paint to make your white underwear appear white.

[1]

Simple color temp won't really give you a good indication.
Using this light for video should work, but to sell it as light therapy is pretty dumb, given the fact that LEDs have an atrocious CRI!!

[zagnut]

The bed sheet only works if it was washed in Clorox
But you are on to something: Laundry detergents contain blue paint to make your white underwear appear white.

You've never seen me do laundry...lmao! Huh...that must be why the only detergent you ever see is blue, other than the hypoallergenic stuff that is dye free.

Simple color temp won't really give you a good indication.
Using this light for video should work, but to sell it as light therapy is pretty dumb, given the fact that LEDs have an atrocious CRI!!

I was just curious if there was an easy way to find out the temp because I like knowing specs. It's easy enough to adjust WB in post a little if necessary. I always set a custom WB in cam before recording, so it rarely needs a little adjustment, if any.
CRI? Whats that? I'm gonna guess and say "Color -something- Index". Buts whats the "something"? I could care less about this thing for depression. I forgot I even had it until tonight. It's been sitting up high on a shelf for about 3 months...lol. I feel bad, because it originally cost $80. But at least it will get used for something

[cgbier]

The higher the CRI value, the closer to the original your colors, but as #1 said, for general video it should be good enough.

[Playing]

Just go through the white balance presets, Tungsten, Daylight etc. Some will be blue and some red. See which gives you white. My LED light fits "Shade".

[Erik Bien]

CRI = Color Rendering Index. While not really designed with digital photography in mind, lights with higher CRI numbers generally yield truer colors.

Beyond a custom white balance, you can also tweak the color with gels if it's a little off (I find one or two layers of 1/4 CTO is usually enough to bring "super-blue" LEDs within spitting distance of "daylight").

[Janke]

For serious photo/video work, the CRI index should be 95 or higher.

Pro halide lights are CRI 96 or so, while halogen incandescents are a full CRI 100.

[Almohada]

isn't it cheaper to just get the 126 LED light on eBay?

[Almohada]

CTB/ CTO filters & gels possibly?

[zagnut]

Thanks for all the info on CRI guys. I appreciate that.

isn't it cheaper to just get the 126 LED light on eBay?

You missed something in my original post...I didn't pay anything for it. Nada, zero, zip, zilch. I'd be curious to see what kind of light one of those el-cheapo, multi-LED lights off e-bay throws off. This thing really is so bright on high, that it can't be looked directly at. And it's only 72 LEDs.

I got A LOT of video and photo editing to do this week, but I'm gonna try and get around to making a battery pack for this thing and measuring the color temperature.

[Almohada]

oops, yeah I forgot that your mother bought it for you... so what I really meant was, if you were looking into this Sad Light Therapy LED light... isn't it cheaper to buy the 126 LED lights from ebay?

[zagnut]

It probably is. I'm not sure what those are selling for, but considering this is $50 through Amazon right now and a battery pack has to be made, and a mounting solution has to be found, it probably is in the end. Battery pack won't take much. Couple $4 battery holders, project box to mount them in, some wire and the correct plug from Radio Shack. Shouldn't be more than maybe $15. But still, E-bay light is less hassle and probably cheaper. Even if it isn't as bright, it's adequate. Just wanted to post this to show how resourceful I am and what can be done with things laying around that aren't being used.

Only advantages I can see this having, is possibly brightness, having a timer in case one is worried about forgetting to shut it off (not easy to do) and possibly the build quality.

Once I get the battery pack made and get it mounted up, I'll post pics and some late night test footage from outside.

[Janke]

I'd be curious to see what kind of light one of those el-cheapo, multi-LED lights off e-bay throws off.

Greenish, possibly with zombie skin tones... before correction. Add an orange filter in front of the light, and it'll be much better...

[Almohada]

Add an orange filter in front of the light

and it comes with one too!

[Janke]

- which isn't really the right color...

[Almohada]

It's not 3200k?

[Janke]

A filter has no Kelvin number. (It can have a Mired shift number - look it up...)

The problem with LEDs is that the spectrum has peaks and valleys, which daylight or halogens don't have.

[zephyrnoid]

CTB/ CTO filters & gels possibly?

yes

[zephyrnoid]

A filter has no Kelvin number. (It can have a Mired shift number - look it up...)

The problem with LEDs is that the spectrum has peaks and valleys, which daylight or halogens don't have.

I do a weird thing (don't I always). I hate flat homogenous filters for correction so I actually dot around on the LED's with sharpies. Salmon, Yellow, Orange. I test gradually by shooting a standard color chart (NTSC swatches) and when I think I'm on the mark, I stop dotting. Call me the Seurat of LED modulation if you will I'll post a pic of the fixture when I get a chance (been in hospital so....)