It’s obvious that LED studio lighting is a trend that doesn’t seem to be going away any time soon. Working in the studio with LED lighting systems, as I did recently with Flashpoint’s affordable ($200) CL-500R LED Circular Light, brings you face-to-face with terms like lux, lumens and foot-candles.
Don’t let that you freak out; there was a time when megapixels were alien too. Lux is a unit of illumination equal to one lumen per square meter or the equivalent of 0.0929 foot-candles. Sekonic offers a chart that compares Exposure Value to foot-candles and lux. Charts, such as Jim Beecher’s, show the relationships of shutter speed to aperture at a given EV for a specific ISO setting so with a little practice you can convert these numbers into shutter speed and lens apertures if only on a order of magnitude basis, such as when you discovered that the Nikon D810 had 36.3 megapixels, you knew “that’s a lot of megapixels.”
It’s not just he way that light from LED sources are measured it’s also the quality of that light—not all LEDs are created equal—and there doesn’t seem to be a direct correlation between price and quality. Although some cheap LED lights reflect their price point others are surprisingly good, just as some expensive LEDs lights are not that great.
To measure this quality of LED (and fluorescent too) studio lighting, I obtained a pocket-sized Diffraction Grating Spectroscope that lets me inspect a light source’s spectrum and actually see peaks and missing bands. You can find these devices that are also used by rock and mineral collectors on eBay or Amazon for about $35. Although your eyes automatically adjust for missing color bands or spikes, your camera cannot and this difference results in time spent or wasted, depending on your interpretation, in the digital darkroom trying to get the color “right.”
For some more tips, tricks and techniques on creating studio lighting effects without spending the big bucks on gear, pick up a copy of my book “Studio Lighting Anywhere” from Amazon or your local camera store.