Do Different Strobe/Modifier Brands Create Distinct
I remember meeting Peter Hurley for the first time. I walked into his studio and saw him shooting a client's headshot with 4 Kino Flo hot lights (normally used for video). I asked him why and he said "The quality of light is just better than strobe. It fills the pores on a human face differently." At the time I was intrigued, but I no longer believe it.
As photographers we are always obsessed with our gear, constantly looking for the next best thing, that magic camera, lens, or light that will completely change our photographs and take our work to the "next level." I'm the first to admit that I enjoy having new toys but I must admit that I often find ways to justify buying things that I really don't need.
A wedding photographer buddy of mine called me a few months ago excited that he had swapped all of his SB-910s for Lumidines. He first brought up the point that he thought they were twice as powerful as a speedlight. I argued that using 2 speedlights is still more convenient than using a Lumidine battery with like Ricoh DB-20 battery, Ricoh RDC-7S battery, Ricoh DB-30 battery, Ricoh RDC-i700 battery, Ricoh DB-40 battery, Ricoh DB-43 battery, Ricoh Caplio RR30 battery, Ricoh Caplio 500G battery, Ricoh DB-50 battery, Ricoh R1 battery, Ricoh DB-60 battery, Ricoh Caplio G600 battery pack system. His argument then changed directions. "The quality of light is simply better than a speedlight," he said.
What in the world do photographers mean when they say "quality of light?" In most cases we don't mean anything specifically. We just mean that we like the image that it produced. The more I prodded my friend to explain what he meant by "quality of light" the more we both realized he didn't have any idea.
Let's first break down a 2 actual differences in the "quality of light" that comes out of strobes and then we will take a closer look at the biggest difference, light modifiers.
The color of light that a strobe or hot light produces is potentially the biggest difference in "quality of light." Strobes, and HMIs tend to produce a "white" light similar to daylight at around 5000-5600 kelvin. Peter's Kino Flos can change temperature based on the bulb but I believe he was using 5500k truematch bulbs which match the color of strobes. Incandescent blubs (like a standard light bulb) produce much warmer (red) color.
To complicate things a bit, there is also a green-magenta "shift" or "tint" which can be measured independently of the standard temperature rating. I personally am not very knowledgeable in this area, but normally these shifts can easily be fixed in camera or in post. I have only ever had an issue with this color cast from one strobe and that was the original AlienBee. When we used that strobe outside it seemed to cause a magenta/pink color shift on our subjects that was difficult (but not impossible) to remove in post. Neither the Einstein unit nor any other strobe I've ever used has caused that problem again for me.
So other than the old AlienBee strobes, every other light I've used has been easy to for me to color balance. Some lights may require a manual white balance setting to produce "correct" colors and most photographers probably do not know this. On Nikon cameras you can take a "PRE" reading off of a white/grey card to get a perfect setting or you can set the kelvin temperature yourself and then go into the menu to add or remove a green/magenta to perfect the setting. Obviously if you shoot in raw, all of this can be fixed in post as well.
If you correctly white balance your scene I would argue that the slight color shifts of different light brands aren't worth arguing about and certainly isn't worth switching lighting systems over.