Depends on your camera and desired framerate. I've shot a campfire scene once before and it was a challenge. I used a 8ft frame with a silk on it, then hit that with a 1k on a flicker generator @ about 50%. Didn't have to light all the way around the fire, just one side, so I set that up about 20ft away from the fire. The actual fire also added some realness and flicker. It was pretty believeable in the end, and considering we were shooting on an Epic with CP.2 (F2.1 lenses), the practical light from the fire just wouldn't cut it.
You can see the finished video here... http://www.youtube.c...h?v=WGXEs-zHJ4M
The areas around the fire are still a little too dark for my taste. I would have liked to see more of the campers from 45-50 seconds in. IMO, it is almost impossible to light a scene like this, when the motivating source (the camp lantern) is in front of the actors, with that source alone. Lighting with separate instruments is almost always required to make the scene look natural.
I don't think you'll have problems with getting exposure from the lamp depending on the lens/camera choices. Barry Lyndon was shot with JUST candle light for many scenes but its not about simply getting exposure when you are lighting a scene it's about setting a mood.
Getting exposure from the lamp is not the issue. The problem the OP will likely encounter is that the lantern will be such a hot spot in the scene that he will not be able to compress the contrast range of the scene into the dynamic range of the camera. If he exposes for the actors, the lamp flames will be overexposed and blow out and lose all detail. And since the light from the single source (the lantern) falls off rapidly, the background will be under lit and detail will block up. As a result, the actor’s faces will look disembodied like they are floating in a black void. As Phillip discovered, shooting a scene around a campfire poses similar challenges.
In order to maintain detail in the flames of the fire you must bring up the surrounding environ a lot and you won’t be able to do that with a few CFLs. For example, contrast the beach campfire scene below to the sample above.
Campfire scene on the beach powered by a Honda EB10000
You can clearly see the subtle differences in color in this fire because the production used 1800W Arrimax HMIs to rim light the actors around the fire and a 4k Par to light the deep background. In doing so, they have compressed the contrast range of the scene which enables them to peg the exposure value of the fire so that detail is held in its’ flame at the same time as there is detail in the deep background. To do that minimally requires 1200w-9kw HMIs depending on the scale of the wide shot.
For a remote site you should try to get a small generator, I used multiple CFL spot lights on a bathroom fixture I got at Home Depot. Test everything out in your backyard before you set out... Hope this gives you some ideas
To power larger HMIs in the woods, I would suggest paralleling a couple of Honda EU6500s. The combined 100A Output should be enough to power a good size HMI (say an Arri M40 4kw Arrimax HMI) to light the deep background and have enough power left over to power not only talent keys but also backlights, rim lights, and kickers to edge light your talent and separate them from the dark background.
The problem with using Hondas in situations like this in the past was the noise they make. To avoid picking up the noise in the audio tracks they would have to be used at a great distance from set which would result in significant "Line Loss" (often referred to as "Voltage Drop") from the long cable run to set. To the problem of line loss, you have the added problem that as you add load, the voltage drops on portable generators (it is not uncommon for a generator to drop 5-10 volts under full load.) The combination of voltage drop on the generator and line loss on a long cable run can cause voltage to drop to the point where HMI and Kino ballasts cut out unexpectedly or won't strike at all. Low voltage can also cause problems such as reduced efficiency and excessive heat in equipment, unnecessary additional load on the generator, and a dramatic shift in the color temperature and in the output of lights. The trick to using portable generators, like the EU6500s, at a distance is to use the generators with a transformer that will enable you to boost the voltage to maintain full line level on set.
Left: Honda EB10000 operating out of a grip truck (note set at distance (bright spot on right side.)) Center: 84A Full Power Transformer/Distro compensates for Voltage Drop over 400ft cable run.
Right: Beach Set with 120v full line level 500ft from power source.
A boost transformer will enable you to add 300'- 400' of larger gauge 250V twist-lock extension cable between the generator and the Transformer/Distro. The heavy-duty 250V twist-lock cable eliminates multiple long cable runs to the generator and minimizes line-loss (eliminating the severe voltage drop you would have using standard
electrical cords.) And, by compensating for the unavoidable voltage drop you will have on a fully loaded generator, a boost transformer will assure full line level (120V) on set.
A good example of how the voltage boost capacity of Transformer/Distro makes it possible to operate portable generators at a distance and maintain full line level on set is the indie short "Paralarva" (pictured above and below.) The film takes place around a campfire on a beach on Cape Cod. To record sync sound without picking up the noise of a generator, the crew ran our modified 10kw Honda EB10000 out of their grip truck 500 ft from their beach set. To assure full line level on set, the production used the boost capacity of our 84A Select Transformer/Distro to compensate for the line loss over the long cable run.
Left: Beach Set lit by two 1800W Arrimaxes. Center: Secondary side power distributed with standard 100 Bates Gang Boxes. Right: Set viewed from generator (note: distance and extent of set power distribution.)
From the Transformer/Distro they then ran 100' of 4/3 Bates Extension to set where they broke out to 20A Edison receptacles using 100A gang boxes. While running the generator near full capacity with a lighting package that consisted of two 1800W Arri M18 Baby Max HMIs, several Tegra 400s, and assorted Litepanels and Quartz Fresnels, they experienced no appreciable voltage drop on set even after a 500' cable run because our Select Transformer/Distro was able to compensate for both the line loss of the cable and voltage drop of the generator under near full load.
By comparison, had the crew of "Paralarva" run 500' of standard 14 Awg electrical cord they would have experienced a line loss alone of 24.5V. To avoid having their 1800W Baby Maxs cut out from low voltage, they would have had to move the generator closer to set where it would be picked up on the audio tracks. This example clearly demonstrates how the boost capacity of transformers can enable you to not only place the generator further from set where it won't be heard, but also assures that the supply voltage on set does not drop too low (use this link for information about Line-Loss and how to combat it.)
Line loss compensation is just one of the many benefits to be gained by using a boost transformer on Honda generators (use this link for details.)
Guy Holt, Gaffer, ScreenLight & Grip, Lighting Rentals & Sales in Boston