Can I modify a Cree Q5 for color temp and high cri?

[tom11films]

I'm a filmmaker, and I'm looking for a light that doesn't seem to exist yet, but certainly should (at least at an entry-level pricepoint). I want a small, battery powered LED with a focusable zoom head on it- to go from flood to spot. It should also have some dimming capability. Ideally the bulb would be 5600K color temp and 90+CRI, but I don't think that's possible quite yet...

So I've been digging around a little, and it looks like this light:
http://www.ebay.com/itm/Mini-CREE-Q...djustable-Focus-Zoom-Light-Lamp-/160798194195
is dirt cheap, and already has a functional zoom lens built in.

I'm wondering is there a way I can swap out the bulb for something with daylight color temp (as close to 5600k as possible) and as high CRI as possible?
If so, what would that bulb be, where could I get it, etc.

I'm even open to replacing the electronics entirely if that's what it takes.


Any thoughts or ideas are welcome, tell me what you think. If I'm going about this wrong, let me know that too, as I'm a beginner here.


-Tom

 

[AnAppleSnail]

Read up on threads about the "Nichia 219" LED. It's 93 CRI and pretty good color temperature. The name "Sunlight in a can" tells (almost) the whole story*. *Of course, sunlight changes throughout the day.

 

[tom11films]

Thanks for the lead. I have been reading about the Nichia 216, as well as Luxeon Rebel ES, and Cree XP-G2 n. I need to research these more, and then I need to figure out if any are swappable for the Q5 that is in that $5 flashlight.

-Tom

 

[tom11films]

Here's what I've found so far:

Nichia 219 4200K 92CRI
max 1500mA 5.25W 40-100C temp
3v max
87lm


Luxeon Rebel ES LXW8-PW50 5000K 80CRI (same size as XP-G) $2.91 @ mouser

180lm
120deg
700ma / 2.9v
3.05mmx4.49mm 1.98mm tall
SMD

Cree XP-G2 N 80CRI 3700-5000K


Cree XM-L2 3200K High CRI version- under 3A only for good color


Seems like that Luxeon Rebel ES might be a good option, it's almost twice as bright as the Nichia, and comes in a 5000K version.

 

[jabe1]

IIRC the Nichia is rated 87lm at 350ma.

From experience, the 4200k of the Nichia seems low. Mine all (5) seem to be around 5000-5500k.

You really need to see one in action compared to some others.

 

[tom11films]

Seems like the Nichia is the favorite in the posts I've read when it comes to high CRI. So the next question is-
can I swap out one of those for the LED in a commercial light that already has a built in zoom to throw function?

 

[AnAppleSnail]

Yes. You'll probably want it on a 20mm MCPCB, and basic soldering abilities.

 

[tom11films]

So I've compiled a big list of cheap FTT (flood to throw) flashlights which might work for this project- at least they have aspherical lens built in, rather than TIR (total internal reflection) style, so they should be compatible with different LEDs swapped out. They have a variety of battery and mode options, though ultimately I'd prefer a knob to adjust the brightness, but that doesn't exist in these lights. Maybe it can be hacked in, or that might require replacing the driver? That will be a topic for another thread.


PALight M900 Cree XMLU2 http://dx.com/p/palight-m900-cree-x...oming-flashlight-black-1-x-18650-26650-173030
1 x 26650 battery and charger included, hi/mid/low, plastic lens, no reflector $33.90

Romisen RC-29 Focasable R4 http://goinggear.com/romisen-rc-29-focusable-r4-neutrall-led-flashlight.html

Sipik SK68 Cree Q3-WC http://dx.com/p/sipik-sk68-cree-q3-wc-120-lumen-convex-lens-led-flashlight-black-1-aa-1-14500-39585

Sipik SK98 Cree XML T6 http://www.manafont.com/product_inf...oodtothrow-led-flashlight-black-18650-p-10046

The best one I've come across is this one:
Yelz T9 Cree XML T6 zoomable big head http://www.cnqualitygoods.com/goods.php?id=1107
plastic lens, requires 18650 battery, 9 modes, most are pointless, fantastic 8-60 degree zoom range $27

Here's another question for ya'll- I've never used this type of light w/ aspheric lens- if you were to put some sort of barn-doors/light shaping on the front, would it cast a hard shadow?

-Tom

 

[AnAppleSnail]

Are you sure you need brightness adjustment? These lights are capable of up to 200 lumens, and that's it. With heavy modification you may reach 500 lumens. An aperture after the lens will cast shadows in 'flood' mode and dim the same-shaped beam in 'spot' mode. An aperture near the LED (Internal) will change the brightness and slightly change the spot size.

 

[tom11films]

Boy, having a brightness adjustment is key- makes life so much easier when you are trying to dial in the right amount of balance between several lights. I know this won't be a very bright light, especially with a Nicha 219- and even more so with a CTB or CTO gel to match daylight or tungsten lights... but if it's being used as a rim/hair light like I'm planning, it doesn't need to be too bright, just a little 'pop'.

When you talk about aperture after the lens- are you saying in flood mode it'll cast a normal shadow, but in spot mode it won't? Or it will, but if the spot is smaller than the shadow it won't?


BTW, thanks so much for your help.

 

[AnAppleSnail]

In general, an aperture (Or object) very close to the aspheric lens will cast a shadow in 'flood' mode, and dim the whole 'spot' in spot mode. If the aperture is inside the head, just over the LED dome (Perhaps a camera aperture from an old manual lens), it will dim the light's output in all lens positions.

 

[tom11films]

Ah, I see. So what happens to those shadows in between spot and flood?

The reason i'm asking is that when shooting video, you often want to cast a shadow to keep from lighting certain areas- for example a bald guy's head- you want some rim light around his face, but it's nice to be able to block light from giving him the chrome-dome look on top. Same goes for white shirt sleeves- you don't want them glowing brighter than the skin of the person's face- it's distracting.

A aperture assembly could work for dimming, but it makes more sense to me to have that done in the electronics- gaining longer run times and less heat in the bargain. Plus it saves the work of re-doing the mechanics to fit a physical aperture inside.