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Sunday, July 21, 2013

••◊ Gam3r-Con and the Radioactive Chicken Heads

Over the last two days I joined the videographer crew for Gam3r-Con, with Tommy and I working as a team.  Today I'm in recovery mode, trying to alleviate the beep-beep-bop-boom-augh-die! of video games from my head.  The concept was fairly simple.  They just wanted a few interviews intermixed with b-roll stuff from the event.  However, when trying to work at these events I find it's best to pair down the equipment list to what's necessary - that only comes from experience or a second day on the job. 

At first I was going to fly a Canon C100 on a Steadicam with the 18-135 STM lens.  That was a bust when I discovered that the lens isn't available for rental in San Diego!  It was probably a good bit of fate that we didn't.  The Gam3r-Con venue is an old theater with old building dimensions - i.e. small and tight.  I was also going to do some stop motion stuff, but the event just didn't feel right for it - so I left the flash home on the second day.

The indoor interviews below were lit with a combination of 1k plus diffusion, PAR cans, and a small battery powered LED light.  For Benja's interview (second picture below) I bounced a 1k PAR off a nearby white wall for fill.  During the dark control booth interview I borrowed a deep red gel from the theater and used that as the separation light.  In all, I think the interviews came out looking good.  The outdoors were a bit more challenging since we didn't have the necessary equipment to re-light an outdoor location. As with documentaries, sometimes it is what it is with what you have available.   


Gam3r-Con hosts a party on the roof nightly.  The first night I was there they had Black Nerd Comedy (yes, that's what he calls himself - have proof.) and the Chocolate Covered Cosplay Girls from Los Angeles with a video game inspired DJ.

Brian (in the first picture following this paragraph) is the co-founder of Gam3r-Con.  He put on his one man show "Gamer", about a man trapped in a cubicle all day doing IT support and the troubles of supporting his gamer addiction at work.  The event also hosted panels, including the panel on video game voice over work (HULK SMASH!).


Of course, my favorite party event was an appearance by the Radioactive Chicken Heads.  When I heard their garage band style I was immediately brought back to the days of attending rock concerts and throwing myself into the mosh pit!  I kind of miss the pit, except for the rancid smell.  You can check out an example of the performance in the video posted below.


Wednesday, July 17, 2013

••◊ Neshima ADR Behind the Scenes Video

We spent the last month and a half at Mediatech in Oceanside doing recording of ADR.  It's amazing how many little annoying noises sneak into the audio when you don't have the best of locations to shoot in, or sometimes just the budget for a real location audio professional. 

I originally thought this would be a documentary style interview/cut-away type piece, but there really wasn't time for that.  The Mediatech studio was only open so many hours on the weekends, and often we had actors coming and going quickly - along with the drummer randomly hitting a snare down the hall at times.  The iso booth was well built, so it wasn't an issue for us inside the Rincon recording studio.

We had three students as our engineers, all doing work as a sort of volunteer intern.  Jarrett, Perris, and Fernando stuck it out until the end.  Congratulations go out to Jarrett, who just graduated this week.

I used a two microphone technique when setting up the iso booth.  One under, one over.  That way the actors could point their mouths in whichever direction and we would pick up decent sound.  We weren't sure which way the mic was pointing during principle photography, so I figured this was the safest thing to do in order to get a timbre match to field production audio.

Anyway...hope you enjoy the little behind the scenes video.

Monday, July 15, 2013

••◊ Sidewalk Film Festival

Over the weekend I received the letter below from the folks at the Sidewalk Film Festival about my bodybuilding documentary.  I just wanted to give a shout out to Kyle and Rachel; two people who actually took the time to acknowledge my hard work with a simple handwritten note.  This is rare in the cold rejection world of film festivals.  This year I've received many rejection letters from film festivals and in one very shameful example a San Francisco based film festival didn't bother to contact me at all, nor updating the film's withoutabox submission status.  Now I know why Alison Bagnall (writer of Buffalo 66) endorsed this festival.  I met Alison at the Bend Film Festival many years ago and she seemed like a nice person, so that's what lead me to submit my film to a not so obvious film destination like Birmingham Alabama.  She was right.

Thursday, July 11, 2013

••◊ video lighting and human vision

It's been so long since I posted that I nearly forgot my Blogger password!  Alas, my memory didn't fail me.  I've been taking a scientific look at LED lighting for video lately as part of a nerd safari in the deep, dark realm of Wikipedia.  This, of course, started after I found out about the new lust-worthy Ikan handheld photo spectrometer - which at $2k is going to remain something I geek-lust after. 

Meanwhile, after looking at dozens of LED data sheets online I was a bit disconcerted that the LEDs that claim to be 3200k (tungsten) and 5600k (daylight) weren't quite perfect - in theory.  Thus is was off to Excel that I went; and down the Internet rabbit hole.

My first stop was the plateau of "black-body radiation".  Color temperature is really described as the color spectrum a black body would emit if it was heated to a defined temperature, say 3200 Kelvin.  Obviously our household tungsten bulbs aren't anywhere near 3200 Kelvin, otherwise every house in America would have caught on fire by now.  However, the spectrum that the tungsten bulb emits is commonly thought of as close to 3200K or sometimes 2700K.  I used Excel to calculate the spectrum of a "ideal" black body radiator using Planck's equation.


After some research I made the graph calculate from 390nm (violet) to 700nm(deep red).  As you would suspect from a tungsten bulb, blue is quite a bit lower on the graph than red.  After doing a quick Google search I found someone who has actually measured a tungsten light bulb's spectrum and in the name of science I ripped off their picture. However, as a courtesy, you can read the original article at this link.  The two graphs seem to agree within reason.  I guess that's one of the reasons why tungsten lights remain the industry standard to this day - very predictable color representation.

However, when we look at LEDs that claim to be around 3200K-ish then things get a bit interesting.  What I found is that LEDs tend to come in 3000K and 3500K more commonly, but the example below is still effective at showing my point.  The graph is from a data sheet for a Cree CXA3050 LED, as you might find in a hardware store "warm white" LED bulb that is meant to replace a tungsten bulb.  With a color rendering index of 93 you would expect this to match a black body radiator pretty well, but it's no where near the same spectrum.  Please note that the Cree LED graph extends beyond 700nm, so this isn't a 1-to-1 graphical representation.  The LED is all lumpy with a large spike in blue, a dip in green, and precipitously falling deep red response.  Somehow that spectrum comes out sort of looking like 3000K.. The second picture is the spectrum of an ideal 3000K light bulb.

So how can this be?  Well...let's start with a simple concept - the spectral response of the human eye.  Again, I stole some graphs from Wikipedia at this link.  The human eye is most sensitive to light at 555nm (green).  Interestingly enough, our peak sensitivity drops to about 507nm at night.  A blue shift...hmmm, wonder why we would do that at night?  Notice how the graph barely leaves zero around 420nm?  In fact, it barely leaves 1% around 430nm.  The same goes for the other end of the spectrum.  We barely see anything above 690nm and it drops to zero around 700nm. 

So just because the LED doesn't produce much light below 420nm doesn't mean that much to human perception of the light source.  Relatively speaking, it's difficult to see!  What is of greater concern is the area up around 650-690nm.  Notice how the "ideal" 3000K bulb is still rising around that area of the spectrum, yet the LED is falling away?

For an explanation of why this bulb appears like a 3000K light bulb we have to dig much deeper into how we, as humans, perceive the different spectrums of light.  There are three types of cones in our eyes: short, medium, and long - identified by the wavelengths they are sensitive to.  So when we see violet or blue it's mostly the short cones that are being stimulated.  As you can see in the picture below (also stolen from the Wikipedia "color vision" article), each cone type has its own spectral sensitivity.  The cone integrates light over the range of wavelengths its sensitive to. 

So when you provide a spectrum like the 3000K LED shown previously, it is stimulating each cone and the cone in turn integrates the light over that spectrum.  For instance, the long (L) cone can't tell the difference between 500nm and 600nm - both frequencies and everything in between stimulate that cone.  The long cone throws both of those frequencies into its stimulus "bucket", but with different weighting.  You could have a light like the "ideal" 3000K black body radiator as shown in my spreadsheet graph, or you could provide an equivalent weighted spectrum like the LED has, that throws enough light into each cone "bucket" to make the two lights perceptually equivalent.

Oh...so that's not so bad, you're probably thinking.  Well...sort of.  It depends on if it's you or a CMOS/CCD sensor looking at the light.  Image sensors do not necessarily mimic the human sensitivity to wavelength.  Also, the dye based filters that are used in Bayer patterns on all our favorite cameras do not necessarily match the cone sensitivity of our eyes.  Your camera may disagree with your estimation/perception of a color temperature based on how it sees color!

The only clear way I see to work around this with the state of the art LED technology is to mix different LEDs to match color temperature spectrum, however that's fraught with inefficiency in light integration and color mixing light guides.  LEDs are just barely getting to be powerful enough for video lighting, so most vendors would probably argue that it's better to have enough light than perfect light.

Hopefully I haven't gone off the deep end.  I DO have a video project this weekend, so I can put my nerd hat back on the rack and my geek member club ID back in my wallet for a while.  Now you know what sort of weird stuff keeps me up at night.