I love LED lights! Almost all of my flashlights are LED. All of my headlamps are LED. Most of my Christmas lights are LED. So naturally when I saw that Costco had some 110v LED lights I had to try them. I wondered how well they would work for a constant light source in a studio. So tonight I tested one, got some data and calculated if they would work out for photography.
LED light in reflector and white paper at 4 feet
Here’s the setup: One LED light, 7.5 watts, 450 lumens output, in an aluminum reflector (chick brooder). An easel with a piece of white poster paper. Nikon d300 with 50mm 1.8 AF lens. I manually set the white balance to 3030K.
I set the easel up at 2′, 4′, and 8, from the front of the bulb. I then determined proper exposure by setting the camera aperture to 2.0 and letting the camera pick the f-stop, I also manipulated the ISO until I could get a baseline. Since I was shooting a totally white piece of paper I knew I would have to add 2 more stops of light for a proper exposure. After a few test shots I choose to set the ISO to 1600, shutter at 1/125 sec and got the following f-stops: 2.0@8′, 4.0@4′, and 8@2′. I then put a colored test chart up and shot it at 1/30 second to confirm my results.
Test Chart: 8' from one 450 lumens LED light, ISO 1600, f2.0, 1/30 sec.
In order to be useful to me in a studio with moving kids and/or pets I want to be able, at a minimum, to shoot at 8 feet from lights, f8, 1/125 sec, and ISO 400. So I would need four more stops of light to get my f-stop, two stops to get my shutter speed, and two more stops to get my ISO. So if my math skills are correct I would need eight more stops of light than one LED produces. Since each stop doubles the amount of light, I would only need 256 of these fine lights to replace one of my strobes. If you have more experience in guessing these things, please chime in.
So yes, the LED’s would work for photography, If you had a lot of money and a lot of room. If you just wanted enough to do head shots, I think eight of them would be adequate. Thats a much more reasonable number to work with. I was thinking of putting a nine light unit together to see how it would work, but since it would probably have very limited usefulness, I don’t think that I will. If you put one together I would really like to know how it works out for you.
