CRI

As I consider adding lights for video to my pool lighting setup, I have run up against the possible limitations of LED lights in terms of their ability to render color or CRI

http://en.wikipedia.org/wiki/Color_rendering_index

I would like to hear from folks who have used both traditional lights and LED on their thoughts in terms of the color rendition of LED systems.

CRI is discussed in this thread. I also had added two informational attachments that may help educate and clarify some things for you. Keep in mind that lighting underwater and topside are two different things. http://wetpixel.com/forums/index.php?showt...20&start=20

Steve

For practical purposes my understanding of CRI or CQS mentioned in the articles you posted relates to the ability of a light source to illuminate a broad spectrum of colors, independent of color temperature. In the diving situation, this may translate to the ability of the light source to illuminate say the many different colors of a reef scene. I would imagine that differences would be much harder to detect in less colorful scenes.

For my pool work the ability of lights to render skin tones accurately and the many shades of makeups and fabrics is of interest. In effect LED lights may render a less polychromatic version of a multicolored subject. I'm just wondering if any folks who have used LED lights underwater have noticed a difference say in the rendition of reef scene colors with LED's

Loftus,

Aren't you then back to having to question the CRI rating of the LEDs themselves? I would assume that would be the first thing to ask, if you were concerned or interested, when comparing LED lights or when comparing LEDs to other light sources like HIDs.

Steve

Loftus,

Aren't you then back to having to question the CRI rating of the LEDs themselves? I would assume that would be the first thing to ask, if you were concerned or interested, when comparing LED lights or when comparing LEDs to other light sources like HIDs.

Steve

I'm not really concerned with the numbers per se; just trying to get a sense of whether folks have noticed any type of color deficit with LED sources versus traditional lights. I am contemplating investing in lights for my pool work. Skin tones are my first priority, followed by color saturation across a broad range of fabric colors etc. Size and battery power are of no concern as I can use regular plug in electrical power. There are traditional underwater movie lights available which are generally warmer. Of course plug in lights could not serve double duty for diving.

LED's have their own advantages and of course could be used for diving.

I'm looking at 3-4 lights which is a significant investment ($4000-$5000) whether I choose LED lights or more traditional underwater movie lights, so I am just trying to get some varied opinions before taking the leap. Right now I'm inclined to go with traditional sources.

I did notice a big difference between my L & M Sunray 2000 LED lights and the Keldan CRI lights in terms of how much more color I was able to see and film with the Keldans. Before then, I never paid much attention to the CRI ratings due to my own ignorance. Once I did research it and then used the Keldans, which are my primary light now, I really noticed a positive difference for the Keldans. They are not inexpensive nor small but more than happy with them. It is kind of hard to say how they will show skin tones underwater since there are masks and hoods covering everything up but if I were shooting a model in the pool, I have a feeling they would be show to be fine on the Vector scope.

Steve

Jeff

LED has a narrower and spikey Spectral Power Distribution (SPD) compared to Tungsten/Halogen, and these spikes can be problematic when you have colors that occur in the range of the lows in the SPD, when recording into the sensor. CRI is based on visible spectrum to the eye, not a measure of photographic quality. LEDs are slowly becoming more prevalent in the set lighting world but there are issues that manufacturers are working hard to remove.

I found this when I used some cheap chinese made LED panels for lighting at night at a party once. I was also using an off camera flash strobe for stills and the color difference between the strobe and LED panel was significant. The narrower band of LED made certain rich colors look dull including skin tones of certain people. I now stick to Litepanels! I've been very interested in the Litepanel SeaSun but stuff I shoot now just makes lighting difficult. You may wish to check those out, especially the 1x1 Bi-Focus.

It's been known that CRI isn't as important as the limitations show up on the sensor output. For pool work, I suggest you buy refundable lights and test, test, test!

I should add that the color depth of underwater subjects is probably more demanding for you in the pool since your models also do fashion. Google Daryn Okada, I know he did a test on LED lights for video and film either last year or early this year. I can't find the pdf on my computer.