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Light meter with digital?


Michael Maier
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Manufacturers often list photometric data for their lighting fixtures in terms of footcandles.

 

ARRI has an app for the iPhone for their various models of lights. There may be something similar for name brand light suppliers, or perhaps they just have that as part of the light specs on the web.

 

But for many of the 'cheap' lights, all they offer is either the wattage, or perhaps 'total lumens', which could be just from general principles rather than actual measured output, and further does not take into account the shape of the light out, given the lens/reflector configuration.

Edited by John E Clark
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probably never find the link.. but there was an article from the DP of the excellent Wolf Hall series .. which alot was shot using an easy rig.. and he found that actually just going around the set with the camera on the rig was the easiest way to set his exposure levels.. (the camera being on the rig admittedly making it easy though.. ).. for the very low light levels being used.. pretty much lit by candles .. he wanted to actually see what he got on the monitor..

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In fairness with the Alexa it is just very difficult to not have light at all.. set at 1600ASA or 3200ASA and with the Leicas or the Masters at T1.3.. there is going to be a lot of light in any place!

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In fairness with the Alexa it is just very difficult to not have light at all.. set at 1600ASA or 3200ASA and with the Leicas or the Masters at T1.3.. there is going to be a lot of light in any place!

 

That you can get a serviceable image with an Alexa with available light doesn’t mean that you don’t need to light a shot. The problem with working with available light is that it is not always what you want for a scene. This trend towards making pictures “without too much help from the electric department” is IMO troubling because the DOP is giving up authorship of the image. If his/her options are limited to what the great Gaffer in the sky happens to provide that day, the creative options are limited. And if by chance the available light does happen to coincide with what is creatively desired, it will invariably change in the course of the production, leaving the editor with a continuity nightmare. IMO, it is better to tame the natural daylight, and use lights to create a consistent and aesthetically appropriate look that models your set and talent as you wish, than to limit yourself to what your dealt that day and take your chances.

 

For example, say the director wants to go for a noir look for his film. Classic noir lighting is high contrast with deep shadows and hard light patterns thrown on the set. The quality (color temperature and hard/softness) and placement of a light is motivated by a source (practical or window) in the scene that is upstage of the talent. Which means, the talent is generally lit with reverse keys motivated by these practical sources. It doesn’t matter how sensitive the camera is because this is not found light. You create it and it helps to have a meter to do so.

 

Guy Holt, Gaffer

ScreenLight & Grip

Lighting Rental & Sales in Boston.

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That you can get a serviceable image with an Alexa with available light doesn’t mean that you don’t need to light a shot.

 

Here’s another example why working with available light hardly ever works except for the most basic quick shot. If by chance the daylight coming through the window just happens to coincide with what is creatively desired, it will invariably change in the course of the production, leaving the editor with a continuity nightmare. If it is a long scene that will take the better part of a day or, god forbid, several days, you will need to control the daylight coming in from outside rather than limit yourself to a window of opportunity. It is better to diffuse and take the direction out of the natural daylight by flying a silk or solid out the window, and then bring in your own consistent lighting. A good example of this approach is an American Experience program titled “The Most Dangerous Women in America” about Typhoid Mary that I lit for PBS. For part of her life Typhoid Mary was quarantined on an island in New York's East River.

 

tmfilmstrip1lg.jpeg

Typhoid Mary in quarantine on an island in New York's East River. Note the view out the window of the East River shoreline at the turn of the century.

 

Because New York’s East River today looks nothing like it did when she was in quarantine, we used a 30' blowup of a picture of the East River at the turn of the century rigged outside the windows of a house in Arlington MA. We wanted to overexpose the exterior by one stop so that it would look realistic and hide the fact that the exterior was a blow-up. As you can see in the production still of the exterior of the actual location used for the quarantine island, we rigged a solid over the porch windows and the blow-up to keep the sun off both. That way we could light the blow-up and interior so that it remained consistent even though the sun moved on and off the porch in the course of the day. To take the edge off the blow-up, we used a single scrim outside the window to help throw it out of focus.

 

tmfilmstrip2lg.jpeg

The actual exterior of Mary’s cottage was the backyard of a house in Arlington Ma with a 30’ blow up of a picture of New York’s East River shoreline at the turn of the century.

 

To maintain continuity between shots, we brought a 4kw HMI Par in a window on one side of the room as a sun source and a 1200 par through a window on the other side as a northern light source. We powered both heads off a dryer plug in the laundry room of the house using a 60A transformer/distro. The two 2.5k Par lights used outside to light the blow-up were powered by a modified 7500W Honda EU6500is through a second 60A transformer/distro. Since the Honda EU6500is could be placed right on the lawn, we were saved from running hundreds of feet of feeder back to a tow generator. Use this link for more production stills of PBS and History Channel historical documentaries where I took a similar approach.

 

Guy Holt, Gaffer, SreenLight & Grip, Lighting Rental & Sales in Boston

Edited by Guy Holt
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A problem they had on Wolf Hall.. if i remember correctly .. is alot of the locations were actual old Tudor mansions with old tapestries and they weren't allowed any lights inside at all.. but it was lit.. with these double wick film candles.. and some fake hollowed out ones with small fixtures inside.. the DP also made a classy point of giving a ton of credit for the whole shoot being do able to his focus puller.. he couldn't even fathom how the guy nailed it with alot of moving shots on an easy rig.. not a dolly.. so it was down to pure skill ..

 

So not having huge lights doesn't always mean its not lit.. or not the Dp,s vision /skill making the look.. I mean Im sure alot of the old school guys would have loved to have 800 ASA and T1.2 lenses.. its progress and a good thing I feel.. even the angle you choose to do a shot with only one light .. you are lighting it how you want.. there are alot of films that look like natural light..(well just abut all of them these days).. but are lit.. but so well that basically no one would ever know.. to be very honest with you, if I may be.. your clip of Mary looks a tad lit to me..

Edited by Robin R Probyn
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In fairness with the Alexa it is just very difficult to not have light at all.. set at 1600ASA or 3200ASA and with the Leicas or the Masters at T1.3.. there is going to be a lot of light in any place!

 

Maybe because I make my livelihood lighting movies, this whole available light approach and lighting to the monitor really bothers me. I get it: lighting takes time, man power, and it isn’t cheap. The high cost of blimped studio generators has got to be one of the biggest hurdles to obtaining good production values on a low budget. Not only are blimped generators expensive to rent, but they also come with hidden costs. Since rental trucks like those from Ryder or Penske are not equipped to tow, you quite often have to hire the rental house's grip truck to tow them. And, since most rental houses require that one of their employees drive their trucks (for insurance reasons), the production has to hire a driver at roughly $575/10hrs - which is probably more than anyone else on a typical low budget crew is getting paid. All of this makes the creation of light expensive. It doesn’t have to be that way. I have used the approach described above (of using step-down transformers on 240V wall outlets and portable Honda generators) to eliminate the need for tie-ins or a tow genny on many of the historical documentaries I have gaffed over the years. For example, I have used a similar package repeatedly at a historical mansion in Easton MA called the Ames Estate.

 

A popular state fee free location, the Ames Estate, like many historical house/museums, does not permit tie-ins and the electrical wiring in the house is so antiquated that it is unusable. Fortunately, they have a 50A/240 volt circuit in the carriage house for a welder they use to repair the mowers they use at the park. Our standard mode of operation when shooting there is to run 250V extension cable from the welding receptacle to a 60A Full Power Transformer/Distro placed in the entry hall of the house. Using a 60A Siamese at the Transformer/Distro, we then run 60A 6/3 Bates extensions, down to the library, to the second floor, and back to the maid’s pantry. At the end of each run we put another 60A Siamese. A 60A snackbox on one side of the Siamese gives us 20A branch circuits. The other side we leave open for a large HMI or Tungsten Light. Now we can safely plug 1200 - 4000W HMIs (or even a 5k Quartz) into our own distribution anywhere to create the lighting that is most appropriate for the scene.

 

Transformer-Distro_Sam1.jpg

(Scene from "Unsolved History" using a 4k Fresnel powered from a 50A/240V range outlet through step-down transformer/distro at the Ames Estate)

 

A good example of this is a show we shot at the Ames Estate for the show “Unsolved History” on presidential assassinations. The show called for a scene of Alexander Graham Bell using the metal detector that he invented to find a bullet that was lodged in President Garfield. Up to that point, the president’s doctors had used the somewhat medieval approach of probing for the bullet in the president’s torso with their hands. To emphasize the more enlightened scientific approach Alexander Graham Bell took we decided to use a strong light flooding the room at his back, as if he had pulled the curtain back to shed the light of scientific reason on the problem. This approach left the president’s attending physicians literally in the shadows, which was fitting thematically since their approach was from the dark ages. To create a crisp light that would cut the smoke in the room in a dramatic fashion, we used a 4k Fresnel in the hall powered through a 60A transformer/distro. In the screen grab above the shaft created by the scope Alexander Graham Bell holds in his hand directs the viewer’s attention to the president lying in the bed. You don’t find this kind of light – it can only be created. And given this approach, even with an Alexa you would still have to light the interior of the room to make sure the president’s attending physicians did not fall too deeply into shadow, or that Graham Bell’s assistant in the forground was not a total silhouette. And given the low budget and tight schedules of historical documentaries, we could only take this creative approach to lighting because I could light the scene with my meters while the cameramen was shooting elsewhere in the house.

 

Guy Holt, Gaffer

ScreenLight & Grip

Lighting Rental & Sales in Boston

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That you can get a serviceable image with an Alexa with available light doesn’t mean that you don’t need to light a shot. The problem with working with available light is that it is not always what you want for a scene. This trend towards making pictures “without too much help from the electric department” is IMO troubling because the DOP is giving up authorship of the image. If his/her options are limited to what the great Gaffer in the sky happens to provide that day, the creative options are limited. And if by chance the available light does happen to coincide with what is creatively desired, it will invariably change in the course of the production, leaving the editor with a continuity nightmare. IMO, it is better to tame the natural daylight, and use lights to create a consistent and aesthetically appropriate look that models your set and talent as you wish, than to limit yourself to what your dealt that day and take your chances.

 

 

 

Nobody said anything about not lighting a shot, I was just answering to Robin about Wolf Hall, which is a very interesting TV Series photographically speaking.

 

Other than that, natural light, available light or cinema lights.. it all depends on the aesthetics of the project.

 

Have a good day!

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  • 1 month later...

Damn Guy Holt, You know your stuff!! Wow, a lot of great useful information. I know a lot of those thing and it has taken me years to understand them. I wish I could work with you, I could learn a lot from you. I always have my light meter with me btw.

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Michael,

 

I realize this all gets confusing, but hopefully this helps....

 

18% gray is NOT middle gray. ANSI standard middle gray is 12.5% gray. The instructions with the original Kodak R-27 18% gray cards said to meter the key light off the gray card, THEN open the lens up 1/2 stop more.

 

Camera manufacturers can get creative with what ISO means and still camera lenses don't measure in T-stops. What I recommend is that you take the camera AND lens you are using, point them toward an 18% gray card and open up the lens until you see a 44 IRE on the gray card (assuming rec.709 type look). Record that lens aperture setting on the camera. Then use the meter and take an incident reading at the gray card position with the white dome pointed toward your key light. Record the aperture value the meter is giving you. More than likely there will be a difference. Then set the compensation on the meter so it agrees with your earlier 18% gray card reading from the camera.

 

Now you should have a fully compensated system where you can take incident readings and in theory they should agree with how much light your camera wants for what it considers "proper" exposure.

 

We have some tutorials on this topic on the Video Gear YouTube page - youtube.com/videogear

 

Stuart Allman

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  • 4 months later...
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.......for what its worth I have always pointed the dome towards the source as well as that gives you the best idea of the light wrapping around a face as a key light fr example....then you think about how to dial up or down the exposure based on how you perceive the wrap of light and fall off in your key areas

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.......for what its worth I have always pointed the dome towards the source as well as that gives you the best idea of the light wrapping around a face as a key light

If you point the dome towards the source, you won't see the wrap of light at all, because it will always be frontal. I think you mean pointing the dome towards the camera.

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