High efficiency light source for low-light conditions

G

guyburns

Active member
BACKGROUND
I'm just about to purchase a GH1 to use as the source for audio-visuals. For about 30 years I've been producing 3-screen audio-visuals, mostly on wilderness themes, and I'm about to migrate them to HD with appropriate changes to the format. It will be a big job, and while I'm learning how to edit in HD and migrate the shows, I thought I would insert some new video clips to liven up the visuals. Thus the GH1.

I will probably get bitten by the video bug while I'm playing with the GH1 and try my hand at new wilderness shows -- a combination of stills and video. I also have vague ideas of getting into short documentaries.

A PORTABLE, HIGH-EFFICIENCY LIGHT SOURCE
That brings me to the subject of this post -- shooting video in low-light conditions. At this stage I have no idea what type of videos and documentaries I will be doing, but I can imagine some of them will involve low-light scenes: people pitching a tent on dusk; early morning around camp; campfire scenes; forest scenes. I may need a reasonable light source as well as a fast lens.

For the light source, before I go ahead and design and build it, I would like some comments from people who have experience in this sort of thing. I have the expertise to design and put it together, but I know little about the light requirements for shooting video.

My idea is to build a 5 mm LED array, say 4 x 4 (16 LEDs), powered by 6 AAA, NiMH batteries. It would fit on a circuit board not much bigger than a matchbox (without the batteries). Such an array would produce about 200 candelas for about 10 hours (or double that for 5 hours using a bigger array) at a beam angle of 30 degrees. I would make it switchable so that the intensity could be easily altered, and have someone hold the light or use a midget tripod. I have built an array of six LEDs for use as a bicycle light, and it was quite adequate for night time riding, throwing light about 6 metres ahead and 2 metres on each side.

The specs of the LEDs are here:

http://www.superbrightleds.com/cgi-...on=DispPage&Page2Disp=/specs/w18015_specs.htm

Or I might choose to use warm white LEDs:
http://www.superbrightleds.com/cgi-...on=DispPage&Page2Disp=/specs/WW7035_specs.htm

I have some questions. Assume I have the stock lens and a 50 mm, 1.4 lens.

Q1: The specs for the LEDs show a spectral graph, give the correlated colour temperature, and the CIE 1931 Chromaticity Coordinates. Which of those would be most useful in generating a custom colour balance for the GH1?

Q2: Is it a sensible idea to use such a light for illuminating people around a campfire? I imagine I would want to keep the effect of flickering flames, so would not want to wash that away with too much artificial light. Would the combination of firelight and LED light bugger up the lighting altogether?

Q3: What about for dim forest shots? And I may want to do interviews in dark alleys (...don't ask!). Also, side lighting in interview situations wouldn't go astray, would it?

Q4: Assuming this idea is not completely half-baked, should I use the white LED or the Warm White?

Any comments most appreciated.
 
Last edited:
Well, you can re-invent the wheel if you want but there already exists a number of battery powered LED fixtures out there. Actually most LEDs run on 12V input so adapting a battery pack for them isn't so hard even when they are listed for AC use. Here some examples:

http://www.coollights.biz/fixture-series-fixtures-c-40_43.html

http://alzovideo.com/alzo_on_camera_video_light_770l.htm

BH Photo among other retailers have a number of options from inexpensive to very costly.

http://www.bhphotovideo.com/c/browse/LED-Lighting/ci/12246/N/4294551087

A small thread here:

http://www.dvxuser.com/V6/showthread.php?t=194658
 
Thanks for the response and all the links. I had already downloaded your commercial clip and it was interesting to find out how you did the lighting. So these LEDs do give quite good results.

Yes, I will be reinventing the wheel, but electronics is a hobby of mine so I don't mind that. It's a technical exercise as much as anything. And a money/weight saver. I may be taking these lights with me when backpacking, so they need to be compact, rugged, light-weight and pack a lot of oomph. And I may be able to overcome the green tint that some of the links mentioned, by incorporating a certain number of red LEDs into the array. I'll use a mixture of 5000K white, 3000K warm white, and red LEDS to try and match the light output from the array so that it closely matches one of the GH1's presets.

I'm hoping to construct a matchbox-size arrray (two matchboxes with the battery and switches) for about $30. And I've decided not to use AAAs. I'll use 7.2 volt Li-Ion.
 
OK, Very cool, please share it with the forum and possibly give instructions for a BIY
super compact Led fixture.

For my lighting I use, Litepanel "1x1" with Li-Ion backpack and a "MicroPro", uses AA
"Litepanel" LED's are the closest to true daylight and don't seem to have as much of the Green problem. I also use two Super9 florescent but the have to be plugged in.

Please post your results...
 
I have four of these, and they are all I keep (and ever need) in my camera bag: http://www.imagewest.tv/servlet/the-240/50W,-50,-watt,-watts,/Detail
They are brighter than my friend's Lite Panels Micro, and they link together with shoe mounts, so I can make a four bank wall of light. I gelled them on New Year's Eve with a free swatch book (it only takes one -cut in a few pieces and taped with clear tape) of gels, so I have near limitless color options for free :)
 
Oh, and if you know the color temp, you can dial it in on the GH1 in increments of 100 degrees Kelvin.
 
majikfraug said:
I have four of these, and they are all I keep (and ever need) in my camera bag: http://www.imagewest.tv/servlet/the-240/50W,-50,-watt,-watts,/Detail
They are brighter than my friend's Lite Panels Micro, and they link together with shoe mounts, so I can make a four bank wall of light. I gelled them on New Year's Eve with a free swatch book (it only takes one -cut in a few pieces and taped with clear tape) of gels, so I have near limitless color options for free :)
Click to expand...



Would this light be comparable?

289324379_o.jpg


http://cgi.ebay.com/35pcs-LED-Light...ra_Flashes?hash=item3ca4ebdea4#ht_6069wt_1167


thanks

------------------

Information from the seller said this light is not recommended for video and used more for photography. So no that link I posted is not good according to the seller for film/video
 
Last edited:
Majikfraug-

So those have a built-in battery right? How long do they take to charge and how long do they typically last?

No dimming or filters, but nice price--especially considering they come with a bracket.

Thanks,
Ron
 
I think I might go down the route of a comer 1800. on camera, has dimmer and diffusers. It is up there money wise but it ticks a lot of my boxes. the comer 900 is smaller in size but has lower output and no dimmer, otherwise i d get that instead.
 
tears2040 said:
Have you used these? I need to buy at least an on camera light and will be going with the one you posted or the one I did, so are there any real world experiences?


Thanks
Click to expand...


I've got a huge thread on it on the videouniversity.com private member's forum with tons of photos showing it's color temperatures, brightness, and battery life. But if I drink enough Bud tonight I'll post some of it over here. lol

Basically, for $57 the Hong Kong 126-LED blows away the POS LitePanels Micro (which is a gumball machine light that costs $300...complete junk), and is brighter than my really nice Switronix TL-50...but is also much bigger.

I won't use it as an on-camera light for my GH1 for event work (weddings) because it's overkill/too big, but it would be nice on a light stand. It would be perfect for regular video cameras, or people using the GH1 with the slow kit lens. The shoe mount sucks worse than the LP Micro, however, so you'd want to modify the mount IMHO...which would be easy since it isn't molded in and the rest of the light body is made much better than the LP.

I shoot weddings, and rarely need a light since I got the 20mm f1.7 for receptions (ceremonies are different..the GH1 fails for those). But my Switronix TL-50 works well...and has a rechargable internal battery which is cool...I don't buy batteries anymore. I probably won't even keep the Hong Kong 126-LED light in my wedding kit at all.
 
swyzlstyx said:
I've got a huge thread on it on the videouniversity.com private member's forum with tons of photos showing it's color temperatures, brightness, and battery life. But if I drink enough Bud tonight I'll post some of it over here. lol

Basically, for $57 the Hong Kong 126-LED blows away the POS LitePanels Micro (which is a gumball machine light that costs $300...complete junk), and is brighter than my really nice Switronix TL-50...but is also much bigger.

I won't use it as an on-camera light for my GH1 for event work (weddings) because it's overkill/too big, but it would be nice on a light stand. It would be perfect for regular video cameras, or people using the GH1 with the slow kit lens. The shoe mount sucks worse than the LP Micro, however, so you'd want to modify the mount IMHO...which would be easy since it isn't molded in and the rest of the light body is made much better than the LP.

I shoot weddings, and rarely need a light since I got the 20mm f1.7 for receptions (ceremonies are different..the GH1 fails for those). But my Switronix TL-50 works well...and has a rechargable internal battery which is cool...I don't buy batteries anymore. I probably won't even keep the Hong Kong 126-LED light in my wedding kit at all.
Click to expand...


Ok since you wont be needing the light anymore do you want to sell it..... I will be doing Music videos and could use at least 1 good camera light even if in your opinion it might be overkill.


Let me know $$ as I will be buying a light within the next 24hrs from you or somewhere else


------------------------------------------
I already ordered and bought the Hong Kong light. Worst come to worst I will use it till I can afford something better and then sell it. I at least needed "some" kind of light and hopefully I can make it work

thanks
 
Last edited:
If you have a DMX controlled RGB LED fixture, you could dial very precise colour temperature settings via a cheap tethered laptop. I have used about 20 or more of these lights recently for a music video.
 
Ron Rodenmeyer said:
Majikfraug-

So those have a built-in battery right? How long do they take to charge and how long do they typically last?

No dimming or filters, but nice price--especially considering they come with a bracket.

Thanks,
Ron
Click to expand...

You know, I haven't actually tested charging time. Can't be more than a couple hours though, and the light lasts for at least two hours on a charge. Actually I have one that's dead, I'll start the charge and see how long it takes :)

Also, ImageWest offers a 10% discount for dvxusers if you call in your order and ask for the dvxuser 10% discount ;)
 
tears2040 said:
Ok since you wont be needing the light anymore do you want to sell it..... I will be doing Music videos and could use at least 1 good camera light even if in your opinion it might be overkill.


Let me know $$ as I will be buying a light within the next 24hrs from you or somewhere else


------------------------------------------
I already ordered and bought the Hong Kong light. Worst come to worst I will use it till I can afford something better and then sell it. I at least needed "some" kind of light and hopefully I can make it work

thanks
Click to expand...

Oh crap, my apologies...I didn't come back and check this thread until just now....I was considering selling...or just giving the light to anyone that wanted it...since I got it for nearly FREE with my "eBay Bucks".

But I guess I'll probably just keep it and use it for off-camera lighting on non-wedding stuff. For $57, it's a killer little light! Just "fix" the mount somehow and mind your white balance. It'll do until you get something better. Good luck!
 
swyzlstyx said:
Oh crap, my apologies...I didn't come back and check this thread until just now....I was considering selling...or just giving the light to anyone that wanted it...since I got it for nearly FREE with my "eBay Bucks".

But I guess I'll probably just keep it and use it for off-camera lighting on non-wedding stuff. For $57, it's a killer little light! Just "fix" the mount somehow and mind your white balance. It'll do until you get something better. Good luck!
Click to expand...


Thank you and my interest are in music videos, documentaries and short movies I truly hate wedding shoots (beyond boring).


Regardless I am here to learn from everyone and apologize if I was disrespectful in any manner.
 
I hate weddings too. Good money, but not worth the hassle in my opinion. Oh and I fell asleep while charging, so I don't know how long it actually takes. Definitely less than six hours though :)
 
You must log in or register to reply here.
Back
Top