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-   -   Will these lights be OK (http://www.dvinfo.net/forum/photon-management/121123-will-these-lights-ok.html)

Paul Kellett May 7th, 2008 11:57 AM

Will these lights be OK
 
Ok,i've got some LED cycle lights.
They're made by a company called lupine,the model is called the betty/
Lupine betty.
Any of you who are into off road mountain biking will know of these lights.
They're the best bike light's on the world,bar none.
They cost me 600,at maximum power they shine at 1400 lumens,and last for 4 hours. On the lowest setting,something like 40 hours.
The battery and lamp is tiny and could easily be mounted on a cam.
I've made a diffuser from a diffuser on a flourescent light.
The settings are stepless from 0 to 100%.
it seems mad for me to spend money on cam lights when i've got these sitting here.
links below.

http://images.google.co.uk/imgres?im...%3Den%26sa%3DN

and here
http://img86.imageshack.us/img86/250...c151398kf1.jpg

Opinions please


thanks.
Paul.

Richard Andrewski May 7th, 2008 03:47 PM

Yes that uses 7 Seoul Semiconductor P4 LEDs. Lumens per watt is around 64 or so which is above average but is doable by todays standards.

http://www.asutsitrail.com/servlet/the-284/Lupine-Betty-Lamphead-$647.00/Detail

Apparently has some kind of dimming or intensity level switches. Doesn't say much about color temperature in the literature though. CRI on most LEDs is notoriously bad and in the 70s on average.

If you're happy with the color temperature and color rendering of the light, why not? Go ahead and tell us about how well it works for you. Its just a question of what you'll use to mount on the camera and where you'll put the battery (on belt or whatever).

Paul Kellett May 8th, 2008 04:09 AM

Hi Richard.
Thanks for replying.
Dimmable,yes, being cycle lights it can be set up a variety of ways,such as "on,off" or "on high,low,off" etc,it's also got "stepless dimming",hold the button on it brightens up slowly to full power then realease the button and it dims back again.
The lamp itself is small,only 50mm across the lens by 40mm deep.
The battery is only around 20x30x60mm.
The whole lot weighs hardly anything,the screw on lens cap is made of titanium.
I've made a Z shaped bracket,i just need to tidy it up a bit,i'll put a shoe mount on the bottom to connect to cam,battery can be velcroe'd to the middle then lamp on top part of the Z.

Colour ??? How do i find the colour,do i shine the light on a white wall then white balance the cam to find the colour ?

Paul.

Bill Pryor May 8th, 2008 08:27 AM

That's one way to do it--white balance for the light. I've noticed that most of the non-professional LED lights, ie., flashlights, and other uses, seem too blue. If that's the case, and you white balance to it, then everything else (shooting outdoors) might appear too warm. If that happens, you might be better off using your 5600 K balance and gelling the light, maybe trying some 1/4 or 1/8 CTO to start.

Paul Kellett May 8th, 2008 12:32 PM

I know what you mean about blue,i also have a HID cycle light and that is blue,but this LED light doesn't look anywhere as blue,in fact it looks very white to me. Not yellow like halogens either.

Paul.

George Kroonder May 9th, 2008 05:12 AM

Quote:

Originally Posted by Paul Kellett (Post 874083)
it looks very white to me.

Unfortunately your eyes and brain combined are nothing the an image sensor and its electronics. Wheras you/your brain will happily compensate for colorshifts and multiple sources so that the view looks acceptable to you, your camcorder will do no such thing.

The only thing it does is whitebalance, but that only works if you're not mixing lightsources with different color temps.

George/

Paul Kellett May 9th, 2008 05:45 AM

Ok so best way to white balance and find out the colour of these lights is,in a dark(ish) room,put light on cam,shine light and cam at white wall and then white bablance the cam ?

I'll post pics and light colour number here then after i've done it.

Thanks,
Paul.

Jim Andrada May 9th, 2008 07:24 AM

Only niggling concern I'd have would be how really "white" the wall was. There are so many different white paints around. Maybe a sheet of good quality white ink jet or laser printer paper taped to the "sort of white" wall would be better. Or maybe a standard 18% gray card.

Just a thought.


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