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 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.
Flash duration is a big deal for certain types of photography which require ultra sharp images of moving subjects. If you were photographing an ice cube being dropped into a drink, you would want every single drop of water to be perfectly defined. Flash duration is one major reason why some strobes cost significantly more than others. Luckily speedlights and Einsteins have extremely fast flash duration at a very reasonable price.
Most photographers would never place "flash duration" under the heading of "quality of light;" they would specifically mention a slow or a fast flash duration, but it is certainly worth considering when purchasing a light.
So that's it. Color and Flash Duration. So many photographers will argue that there is something else which is "changing the quality of light" but nobody can actually explain to me what it is. Even if there was some sort of magic flash tube that could make images look "better," wouldn't that "magic" be lost when you put it behind a modifier?
I would argue that the light produced from slightly different bulbs or tubes don't have a "unique quality," but the lighting modifiers do, to an extent. The reason that Peter Hurley likes his Kino Flos so much is not because they do something that no other light can, I think he likes the quality of the images produced because the shape of the giant Kinos super close to a person's face produce a very unique image. I believe that any light that size would produce the exact same "look." Obviously a 4 foot florescent bulb will produce a completely different "quality of light" than a 1 inch strobe light. Luckily we have modifiers that we can add to our lights to change their size and shape.
There's a lot of hocus pocus flying around the internet about flash modifiers and for the most part I think it's pretty silly.
For the most part, quality of light can be effected in 2 ways:
1. The size of the light source
2. The distance from the light source to your subject
The shape of a light source can help as well but it isn't as important as many people make it out to be.
Softboxes are the standard modifier that I will compare everything else to. At it's core, a softbox is simply used to turn a small light source into a larger light source. You can buy totally different sizes of softboxes in a range of different shapes but I would argue that their size is the biggest defining feature. Most softboxes have inner baffles that "soften" the light even more. This simply means that your light will leave the front of the softbox more evenly from edge to edge. I've had photographers argue with me that softboxes need to have white interiors rather than silver or that they only use Softlighters because the light is "so much softer" and I'm not buying it. If you want "softer light" simply use a bigger light source. If you want more contrast in your lighting, move your light closer to your subject.
The Fstoppers FlashDisc is simply a mini softbox for a speedlight. I've read reviews online of people saying that the "quality of light out of the FlashDisc is incredible." Although I appreciate the glowing reviews, there isn't any magic going on, it's simply making your light source slightly larger than a standard speedlight head. It's convenient, and helpful in certain situations, but it will produce an almost identical "quality of light" to any other flash modifier that is about that size.
Umbrellas come in 2 basic types, bounce and shoot through. In most cases shoot through umbrellas will produce "softer" light because the entire umbrella is lighting your subject and "bounce" umbrellas will produce slightly "harder" light because they have a tendency to light your subject with the center of the umbrella. White umbrellas will produce slightly softer light than silver umbrellas because white umbrellas will "fill" with light and then reflect it back at your subject while silver umbrellas have a tendency to "reflect" light directly, from the center of the umbrella, at your subject (like a mirror).
The biggest difference between an umbrella and a softbox is that softboxes contain the light spill a bit better. Umbrellas tend to throw light all over the room but I would argue that it is possible to take an almost identical image with either a softbox or an umbrella of similar sizes.
Beauty dishes and Molas
Dishes are a unique lighting modifier because they are changing the size of the light but they are also changing the edge of the light or the "light falloff." A standard beauty dish uses a center plate to reflect light back toward the dish. The light then reflects off of the sides of the dish and hits the subject. The sharp edge of a beauty dish can be used to produce unique shadows on your subject but the lighting itself is very similar to a medium softbox with the front diffusion panel removed. Adding a "sock" to the front of a beauty dish makes it "softer" and even more similar to a standard softbox.
Molas are very unique and expensive brand of beauty dishes. Many of them have very unique shapes which add to their intrigue. We put these units to the test with Peter Hurley in our "Illuminating The Face" tutorial and we found that these modifiers produced an almost identical result to similarly sized octabanks without front diffusion panels. They are certainly impressive to look at and they produce unique catch lights in your subjects eyes but other than that, there isn't any magic going on.
Grids are used to change the "throw" or "spill" of light without effecting the size of a light source. You could put a grid on a flash directly for a very "small" and "hard" light source or you could put a grid on a 7 foot octabank which is "large" and "soft." The grid will help you direct which parts of your scene are being illuminated without changing the size of your light source.
Reflectors could be considered light sources too. The size and distance of your reflector to your subject works exactly the same as a softbox. The shape of some reflectors allow you to craft the light in a way that would be difficult to do with softboxes, but in many cases could be replicated with a piece of white foam core.
Where did this "light quality" crap come from?
So then what is this "quality of light" that photographers like talking about? Perhaps one of the reasons that we are constantly confused by lighting equipment is that we are comparing our unedited work to highly edited images online. We see a picture and assume that it looks amazing because it was photographed with a Profoto Beauty Dish when in reality it has a unique "look" that was produced in Photoshop. If you tried to reproduce the original raw file you would find that any similarly sized light source would be capable of producing an almost identical shot.
I remember years ago trying to reproduce the lighting in the StarTrek movie poster. I could not figure out how in the world the photographer was able to produce highlights on the side of his subjects face and then dark shadows on the cheek bones.
We spent hours in the studio trying to reproduce this shot with lighting alone and finally gave up. I ended up creating a similar look in Photoshop by simply burning in the shadows on my forehead, nose, and cheek. I always felt like I had "cheated" but I was able to create a similar looking shot.
A year later I ran across the original image of Chris Pine from this shoot. Guess what? It looked exactly like my attempt. Those shadows that seemed so impossible to reproduce were in fact impossible to reproduce in camera.
I thought that the photographer knew something I didn't. I thought the photographer must have owned some type of specialized light to produce such unique shadows. He didn't. He used 2 lights in the back and a medium softbox or reflector from below. The "magic" was added in Photoshop.
No matter how much we want to believe it, there really isn't any piece of gear that is going to automatically take your photography to the next level. You can take a horrible or incredible shot with almost any camera or lighting brand, new or old. Lighting is certainly still important, perhaps the most important thing, but the brand name isn't going to make a difference. I'm now using Profoto D1s and B1s. I absolutely love the convenience air remote system, the size and weight of the monolights, the simplicity of Profotos speedring, and the quality and range of their modifier line but I can't tell any difference in the "quality of light" that comes out of Profoto flashtubes compared to my speedlights, or the old Dyna-Lites that I used to own. I believe that the "quality of light" argument is bullshit. I think we make stuff like this up to justify buying new gear that we don't necessarily need but I would love to be proven wrong. Feel free to let me know just how wrong I am in the comments below.