Tom Robotham talks about his Blender LED light
February 9, 2009
LED lighting is changing the way we light, especially run-and-go documentary. There are several units on the market including lights from Zylight, Litepanels, and the new Blender light, designed by Tom Robotham. Several months ago Tom came to visit me at MassArt and brought along his new light. We spent some time experimenting with it and here’s our conversation.
David: You’ve been a working cinematographer for a long time, what lead you to the development of the Blender LED light?
Tom: A couple of things came to a confluence. One was that I had been working on variable color temperature lights for a number of years. The reason I was doing that is because when I was doing narrative work every once in a while I would need something as a fill, as a special, as an edge, not as my primary light, because I’m usually color balancing to whatever is my key light sources, I wanted something and I wanted to be able to finesse it a little bit this, a little bit that, and be able to do it on the fly and by eye. So I had been playing with that notion. That’s one stream of information. The second one, and the primary reason for this is I started doing more non-narrative work, and in particular, I was in a situation where I was working in a very busy hospital, a very sensitive situation because of the patient care and it being pediatrics, and we were having some filming and some interviews that were near windows, and then we were going into a hallway, and interviewing doctors and nurses in a hallway on the fly and once they got beeped they had to leave, so we had to work fast. And then we’d be in an interior office and be able to have a formal interview and there might be incandescents as well as office fluorescents, so it was always a mixed light situation, it was always in a hurry, I very much wanted light that could be slightly off to the side, so it wasn’t a direct on-camera fill, I wanted something to be able to hold out to the side and have a sense of directionality. I played with, used, rented, LED lights and it was never quite easy enough, fast enough, to get what I was looking for to appear natural. And my source was always sort of insistent and visible. And I wanted it to just blend in and augment the available light. I did not want it to be calling tremendous attention it itself. So I grafted these two ideas together: the variable color temperature and the availability of high power white light LEDs that can be obtained on a black body locus. I worked through all of the technological issues to make it both something that was unique in the technology sense and easy to use.
David: For our readers who are not cinematographers, could you explain what you mean by “LEDs that can be obtained on a black body locus”?
Tom: In the 1930s people decided in France that there would be this large commission that would decide how much available light there is and what are all the colors. This is the CIE Chromaticity chart. Inside that is a line that tracks what we perceive to be white light. White light is what we’re primarily concerned with for film/video imaging, because that’s what we’re used to from the sun, approximately from fluorescents, from movie lights, from all of the different sources we’re usually using white light. And that white light is something that is tracked within this CIE Chromaticity chart.
David: But all white light is not the same, is it?
Tom: No, and especially when you go to most modern sources, and I’m not going to claim all, I’m a cinematographer, not a spectrophotometry expert, but you’ll see a lot of light sources that are both discontinuous spectrum and you’ll see a lot of light sources that don’t provide all of the available wavelengths and things like that, but they are close to the black body locus that white light Planckian locus, that curve that our mind says, “oh, it’s white light” “it’s not too green, it’s not too magenta, it’s not too amber, it’s not too blue. Now it is possible to obtain high power LEDs.
I have custom orders that allow me to select things that are on the black body locus. And that’s one of the functions that I want because I don’t really want to be messing around with a lot of plus-green or minus-green gels if I don’t have to. I want to eliminate all of that and be able to work by eye. So it was essential for me to land on a spot that corresponds to the world and how we perceive white light and what’s photographically acceptable as white light as a starting point.
David: A lot of LED lights come as either tungsten balance (3200K) or daylight balance (5500K) and you have to use gels with the lights if you want to change their color temperature. Now there’s something really different about the Blender, I can adjust between the two with knobs. Tell me more about that.
Tom: By having banks of these. For years I had used things like Kino Flos and other fluorescents that allow you to mix and match daylight and tungsten units, and boy it sure is nice to have half and half sometimes, or one daylight unit mixed with the tungsten, it will be just a little bit cooler, but to have two banks of what are nominally daylight and tungsten white balanced lights, I could dial-in all of my variable situation where I could be one sixteenth more warm, slightly more cool, and I could do by eye what I have always liked to be able to do, which is do something like have a back light be slightly cooler, or have my key light be slightly warmer than the ambient, so I don’t change my white balance, or anything, I can just dial in without having to use any gels, working by the monitor and my eye is trained so by my eye as well, what are warm and cool values that match the natural world and then have the artistic leeway to slightly warmer or slightly cooler, if I choose to.
David: So this light has two banks of lights, and it has two knobs and one switch. So it’s pretty simple to use.
Tom: It’s very straightforward, I’ve had students use it, and once they use it they see immediately what happens.
David: So tell me about some Blender usage scenarios.
Tom: I’ve used these in situations where I’ve had subjects near windows, and I’ve wanted to do what you would call carry the light from the outside. And I’ll bring this on the opposite side of the camera closer to the window and have that cool light from the window wrap more around the face of my subject which it doesn’t do on its own. And then have a second light, perhaps slightly warmer, coming from the inside, indicating the interior light. So I get a fully rounded form that matches my daylight, it can be close enough and bright enough that I can actually expose for the outside world and I have a sense of the presence of the world.
David: Can you share another scenario?
Tom: We were in a building with office fluorescents with a number of people doing a series of interviews. And one thing that was particularly interesting is that we were using the Blender light as a backlight, these were standard office fluorescents, they were somewhere between 3800K and 4200K approximately in terms of correlated color temperature, so they are in between value already. We had actually, for the first subject, used a fluorescent light that had 1/2 daylight and 1/2 tungsten bulbs in it that we were using to match the office fluorescents. Well, the second subject came in and their shirt was much brighter and we didn’t have flags, so here we had approximately a 15 lb. rig lighting as our key light, and we substituted it with one of my Blender lights. We brought it a foot closer, it’s a very bright light, but not too aggressive and not too intimidating for a subject. And just by tilting it up and taping a piece of office paper on it, because it doesn’t get hot [like an incandescent] we were able to flag the guys shirt, it cut perfectly with movie fluorescent we used [in the previous shot], and our backlight was slightly cooler. We were in an office environment and we were able to use it as a key and a kicker.
David: How bout one more?
Tom: Shooting run and gun hand-held in a hallway with fluorescents, with windows, with all sorts of wacky stuff, hand-held with a wooden handle off to the side. I was doing the interview, someone else was shooting. I could have a little bit of directionality. I just did it by eye, and we could roll in thirty seconds, cause we had the light out and plugged in to a battery.
David: Sounds like you might want to have a special pistol grip with the Blender light and a microphone on it.
Tom: That actually is not a bad idea, because sometimes it means asking the sound guy, “hey, you’re booming, can you hold this off to the side so it does not have to be on camera?”
David: That brings me to the thought, the miniaturization of these video cameras has really changed the way we shoot. The cameras are getting smaller, it changes what we shoot, how we shoot, what we can shoot. Well, now we’ve got LED technology that’s getting brighter and cheaper, and it’s changing how we light. How do you think these smaller LED lights like your Blender are going to change how we shoot, and what we shoot?
Tom: I think there’s a couple of things. One, they have sufficiently low power usage, it’s nice that they are more environmentally sound, but for us as shooters that’s way down the list, in terms of what it is that we need to shoot professionally, but it’s nice that you can run them off batteries, that you can run for an hour, you can run for two hours, and you’re OK to go. You can’t really do that a lot of the sun guns and tungsten types because they really drain power a lot more. So suddenly we’ve become a lot more portable. A secondary thing, and something that really surprised me with the Blender light, you end up lighting a bit differently than you would normally. Now I was going towards this myself, so I was not aware of it, until I put it into the hands of other shooters, and have them say, “Aha! I’m doing this now,” I was really surprised, because suddenly, instead of creating a light that is sort of obvious, and it becomes your key light, and it’s clear that you have lit the situation, which is what you see in a lot of interviews, you can actually dial this down, raise your subject to a level where you can control attention, but it’s not obvious. So it’s a naturalistic light in way almost like bounce sheets are. I don’t know about you but there are some times when I would rather have nothing plugged in, I’d rather have like a silver bounce here, and a white bounce there, or negative fill over there, and be done, because it can be very naturalistic, and embed your subject in their environment. As long as you can control attention, and you’re not busy looking at the background, you can actually focus on the subject, you’re good to go. Well, these work, because you can blend them almost like bounce sources that have intensity. And so you can approach it in a much more naturalistic way, and you might find yourself placing the light in a different place than you would normally, because it reads as if it was part of the environment, you might find yourself putting it someplace and dialing it very warm or very cool and saying, I wouldn’t necessarily go that far with another light source, but it feels like it’s the light from that other room, so I can get away with something that’s a little more tasty or more interesting.
David: I imagine the Blender will be popular not only with professionals but with newcomers as well.
Tom: For the people who are not coming into this by being technically savvy, they are coming in because they want to make images, they want to make motion pictures, they want to make narrative, non-narrative, whatever it is they are trying to do, they are not coming from a trained background, they are coming from a place, “these tools let me do stuff, I just want to do stuff,” well, here’s a light that allows them to just set it on auto white balance, or they just white balance to the available light, they can now dial in, look at their monitor, and they don’t have to consider what are the correlated color temperatures of those fluorescents, what’s coming in that window, is it sky?, is it day?, is it sun?, what’s coming from that desk lamp?, is it halogen?, is it incandescent?, you can work in a more intuitive way by eye, and I think that’s a huge difference in terms of making motion pictures imaging function the way us professionals are used to in terms of control, and putting that level of lighting control into the hands of people who can now use cameras, because there are now so many nice aids and assistance to making a nice picture with a camera, now there’s that level of assistance to making a nice picture through the aid of controlling your lighting, controlling attention to the subject.
David: I’ve put together a minimalist on-the-go documentary kit in which everything has to fit into a carry-on size hard case: camera, microphones, cables, batteries, accessories, maybe I’ve got room in here for a Blender. How do I attach the light to a stand or my camera?
Tom: I provide a swivel mount, it’s a 1/4″-20 thread on the bottom, I also have a wood handle, which is actually adapted from a file handle, with a 1/4″-20 stud on it.
David: Does that come with the light?
Tom: It’s an optional accessory. The people who want it, who want the light off to the side, immediately say, give me the handle, because they are running and gunning it. The people who say I don’t care about that, well, why bother loading them down with it.
David: What about powering options?
Tom: There are a couple. One, if you’re using a 2/3″ professional video camcorder, and you have a power-tap, D-tap it’s called, all you need is a 2.5mm center-positive connector on the Blender end and you can run this light. And at 14.4 volts you’ll be getting hours and hours of running time.
David: What if I’m using a smaller camcorder like the Sony HVR-V1U here?
Tom: Optional sleds. What I have are battery sleds that come in many different flavors to fit Panasonic, Canons, Sonys, and what I do then is custom wire them so you can use your existing camcorder batteries and not have to invest in a new battery system.
David: That’s handy, since I don’t have a lot of room left in this case for a whole new set of batteries. I’d love to be able to use the same batteries, the same battery charger, as I use with the camcorder.
Tom: I do not like extra battery systems, I don’t like going into a hotel and making sure every different charger is plugged in (laughter) I just want one battery system, so I knew that this would function that way.
David: With one of the camcorder batteries I have here, how long can I run the Blender?
Tom: They look like 2,800 mA batteries, or something like that, so it will last about an hour and a half, that’s what I’ve tested it, from an hour and thirty to an hour and forty minutes. Now there are two things that are worth noting, as it drains, it does not change the light output, what will happen, is this will simply blink off when it’s done. It does not change the light output as the battery drains. The electronics raise the voltage to the base level needed for the LEDs. It’s meant to accommodate [a range of sources] and it will simply blink off [when the voltage falls below a threshold].
David: Do you have plans for larger units?
Tom: Yes, this light, what you might call “pint-size,” is only the first in the line. The design is scalable and we will be making larger units in the future.
David: How can people purchase a Blender?
Tom: Blenders are currently being manufactured here in the United States. They can be ordered from my web site at blenderlights.com.
David: Good luck with the light, Tom, it’s a great idea.
Tom: Thanks so much, I appreciate you taking the time.
Update: Since I spoke with Tom, he has entered into an exclusive manufacturing and distribution agreement with Lowel who will be manufacturing and selling the Blender light. LED lighting will continue to make serious inroads into professional production, especially in run and gun documentary and ENG production.
Keywords: Light, Lights, Blender, Lowel, Interview, Tom Robotham, Lighting, Video, LED