Video Gear: January 2014

One of our reps left a neat toy in the shop for us to play with; a UPRTek MK350N Spectrometer. This handy dandy tool measures spectral response, correlated color temperature, color rendering index, light output, dominant wavelength, and CIE coordinates. It's every lighting geek's dream!

Many video lights claim to have a 5500K or 3200K CCT, but do they really? How good are LED and fluorescent bulbs...really? The data below doesn't lie. I've labelled each data set for convenience and comparison.

Here are a few points to watch.

Tungsten still produces the highest/best color rendering but the color temperature drops quickly with dimming. Also note that the color temperature isn't necessarily 3200K as most people assume.
LEDs are reasonably stable over dimming. Note that all "daylight" LEDs have a large blue spike around 450nm and die off starting around 640nm. Of the group, the Mole-Richardson fixture had the most on-target CCT and best spectral characteristics.
The CCT of the HMI fixture depends on which mode you have the ballast set to run in. The CCT also changes with dimming.
All fluorescent bulbs have a spike in green and blue, as shown in the Kino-flo pictures below. We have tested a couple fixtures and found it's pretty typical for the Kino-flo K55 tubes to actually be closer to 7000K! Commercial lighting fluorescent bulbs (not shown, but I tested them too) are much, much worse!