I'm shooting a short film that is set entirely inside a car soon. ...The whole film is one setup in terms of camera, mounted to the car bonnet, on a 35/50mm lens to capture a medium two shot of a driver and passenger in the front seat, jump cutting between different days/months....For my main lighting setup, I have planned... to hang LEDs either side of the car, lighting the drivers and passenger side depending on the setup. My two main lights are flexible 1x1 LED panels, that also clamp into a solid 1x1 frame. ...This lighting setup will allow me to increase/decrease the intensity of the LEDs either side of the car depending on the look I am going for, whether that be a soft 'overcast' daylight, or a harsher 'sun' coming in from one side of the car, with softer skylight from the other side. ...These are just some of the basic ideas I have had so far. I was wondering if anyone on the forums has had experience lighting this kind of setup with LED lights? Would be great to hear some of the tricks/tools you used to enhance the naturalism in the lighting. ... If I chose to add any lighting in front of the car, for example each side of the camera, would these lights show up as reflections on the screen? Or is that more of a problem with lights hitting the front of the car from above?
I’m afraid your LED 1x1 Panels are not going to be enough to light the interior of the car on day scenes. On car setups like this you face an extreme contrast problem during the day. If you were to expose for your talent, even with the LED panels on, the exterior as seen through the back and side windows will blow out. If you expose to hold detail in what you see outside the car, your talent is under lit and will be underexposed. The problem is that you are shooting into a black hole. To the contrast problem a second problem is that when the windshield glass is backed by black it becomes a mirror and will reflect the sky above. The challenge of these set-ups is that you need to both pick-up the levels inside the car (not easily done with 1x1 LED panels on a bright sunny day) as well as eliminate whatever it is (usually a bright sky) that reflects in the wind shield. Below is a picture of how a big budget movie approaches these problem.
Note that they have rigged an 8x8 solid out over the windshield so that only black will reflect into it. They are also using an Arri M40 4k HMI (equivalent output to a 6k HMI Par) to pick up the interior of the car. Because all this gear obstructs the view of the driver, but also because it is quite often too much for an actor to act and drive at the same time without getting into an accident, the big movies tow the picture car behind a camera truck with an onboard generator to power the lights.
If a process trailer like that pictured above is not in your budget. A less expensive alternative is to rent a “car carrier” to tow behind a pick-up truck. A number of low budget indie productions I have worked on have done this with great success.
A partially built car process trailer. Rosco Scrim still needs to be applied to windows and a 8x8 solid still needs to be rigged to the roof rack.
To reduce reflections in the front windshield, you should likewise rig a large solid on top of the car. To also reduce the contrast range inside the vehicle the solid should extend several feet out on all sides as well. This way you will not have to deal with any direct sun on your talent and can light them through the front windshield for better modeling and continuity.
To reduce the size of HMI that you need to light your talent, you can reduce the contrast between the interior and exterior of the car as seen through the back and side windows by putting Rosco Srim #3421 over them (any window that will appear in a shot.) This scrim will act like a Neutral Density gel and reduce the intensity of what is seen through the window by allowing a specific amount of light (two stops) through fine holes in the material. When it is slightly over exposed you don’t see the scrim itself but just what is on the other side. It is better than Neutral Density Gels in this situation because it is more pliable and less likely to wrinkle and shimmer as the car is traveling down the road.
Even after this contrast control, you will still need a light that is larger than what you can power with an onboard battery or through the car lighter socket. Car lighter sockets are only capable of handling a couple of hundred Watts at most and you usually require at least a 400-575W HMI to light your talent during a day scene. To power a small HMI on the hood of the car you can use a "Battverter" - which is a Battery/Inverter system. A "Battverter" system consists of a 12V DC power source (usually large Marine Cells), a DC-to–AC True Sine Wave Power Inverter, and a Battery Charger. Wire these components into a Road Case or milk crate and you can put it on the floor in the back of the car.
Here are some production stills that show you two Battverter systems I built to run lights in vehicles at various times. The first is a 750W "Battverter" rig wired into in Calzone case.
To maximize the running time on the batteries, I made up a "jumper cable" that we attached to the leads of the pickup truck's battery. That way the engine alternator charged the batteries as they were being discharged by the light. Tie–ing the Battverter into a vehicle engine will extend the running time on your Battverter batteries so much that they may never run out of power.
The production stills below show a more elaborate 1800W Battverter system that I built to run 16 - 4’ kinos tubes inside an airport shuttle bus. Use this link - http://www.screenlightandgrip.com/html/shuttlemailintro.html - for details on how we wired it into the shuttle bus.
Kino Flo 4x4s rigged to an exo-skeletal frame of a Shuttle Bus and powered by an 1800W Battverter
Custom 1800W BattVerter powers 16 - 4' Kino Flo single tubes rigged
in the interior and on the exterior of an Airport Shuttle
When building these rigs, keep in mind that when voltage goes down, amperage goes up. Wire that carries 12V DC has to be much larger than that which carries the same load at 120V AC. For instance to supply 12 volts to the 1800W inverter used on the shuttle bus required that we run 2 Ought feeder to the bus' alternator. Also be sure that
the alternator is large enough to take the load without burning out.
Finally, You have to be really careful when choosing a DC-to-AC inverter for film production because there are three basic types of inverters and not all of them are suitable for all types of motion picture lights. For more information on what type of inverters to use with different type of lights I would suggest you read an article I wrote about portable generators that is available online (use this link.) Since inverter generators use the same three types of inverters, the information in the article is applicable to stand alone DC-to-AC inverters designed for use with batteries as well.
If you don’t want to tie batteries into the car’s alternator, you should consider using a small portable generator. But, you don’t want to use a generator, like the Honda 2000, whose fuel is gravity fed to the engine. The size head it can power is limited and the fuel will slosh around and cause the generator to run erratically. I suggest you instead use a generator that has an electric fuel pump like the new fuel-injected EU7000. The fuel pump assures that the engine receives a continuous feed of gas. When used with a 60A transformer/distro, the EU7000 is capable of powering HMIs up to 4k and it is so quiet that you will not hear it in the car with the windows closed. As you can see from the picture below of another rig, a generator this size with a 60A transformer/distro is cable of powering even a couple of 2.5 HMIs for daylight fill.
A 7500W modified Honda EU6500 powering a couple of 2.5HMI Pars on a car rig.
If you have any questions about using inverters or generators, I would suggest you read the article I wrote on the use of portable generators in motion picture production mentioned above. Use this link to read it on-line for free.
Guy Holt, Gaffer,
SceenLight & Grip,
Lighting Rental & Sales in Boston.
Edited by Guy Holt, 03 April 2016 - 01:07 PM.