Testing LED Lights for Portraiture

by | Jul 23, 2018

Today’s Post by Joe Farace

Here are a few common questions I get whenever I write about using LED lighting for portraits:

  1. How bright are they?
  2. Are they really daylight balanced.
  3. What’s the quality of the light

The answer to question #1 is not very but they are getting better. Many LED lights are rated in lux (luminous flux), a definition that doesn’t help most of us, especially when it affects the inverse square rule that “an object twice the distance from a light source will receive a quarter of the illumination.”

And yes there are problems lurking in some LED light sources: Take the above sequence, for example. It’s not a bracketed series because all three of these unedited frames were made at the same exposure—1/60 sec at f/2/8 and ISO 800. That’s because some LEDs lights exhibit a problem called Pulse Width Modulation that causes flickering that lets them appear to be producing continuous light when specific LED elements withing the light may not be and in fact are flickering off.

Experience in the movie industry show that most exposure meters are not properly balanced to read LED light output and that can sometimes result in inconsistent exposure. One way around that by using the (expensive at $1,362.59) Sekonic C-800 SpectroMaster Spectrometer that’s capable of reading all light sources whether they’re LED, flash, incandescent, HMI, fluorescent or even the natural light spectrum.

When shooting with mirrorless cameras or Live View with a DSLR, you’ll have an advantage because you can see exposure variations in the viewfinder right away, no chimping required and you can re-shoot if necessary.

The answer to question #2 is “it depends.” Some LED light are daylight balanced and some models allow you to adjust color balance, while others say they are but are not. The Rotolight Anova Pro 2 Bi-Color, that I used to own, offers light in variable color temperatures from 3150 to 6300K. To analyze the quality of lights when testing LED lighting equipment for Shutterbug or this blog, I’ve always used a (no longer available) Rotolight Spectroscope. This device is similar to spectroscopes used by rock and gem collectors to analyze the quality of light being reflected by a stone and are available on eBay for affordable prices.

Lastly but maybe more importantly to the portrait photographer is that the quality of the light output from most LED light sources can seem harsh and in the past some of my portrait subjects complained about it and yet it didn’t bother others. When that happens, I’ve used a lighting modifier, like a shoot-through umbrella or softbox, and that seems to do the trick.

How I made the above image: Camera was a Panasonic Lumix GH4 with Olympus 45mm f/1.8 lens. Lighting was two Flashpoint LED lights. Background was a 5×7-foot black Savage Infinity vinyl background. backdrop. Exposure was 1/60 sec at f/2.8 and ISO 800.

If you’re interested in learning how I shoot portraits and how I use cameras, lenses and lighting in my in-home studio and on location, please pick up a copy of Studio Lighting Anywhere which is available new from Amazon.com for $22.75 or used starting around four bucks, as I write this. The Kindle version is $19.99 for those preferring a digital format.