How Big a Light do I Need?

Experience goes a long way, but sometimes you need to be more precise about what size of lighting instruments are required for a particular scene. Night exteriors, for example; you don’t want to find out on the day that the HMI you hired as your “moon” backlight isn’t powerful enough to cover the whole of the car park you’re shooting in. How can you prep correctly so that you don’t get egg on your face?

There are two steps: 1. determine the intensity of light you require on the subject, and 2. find a combination of light fixture and fixture-to-subject distance that will provide that intensity.

 

The Required intensity

The goal here is to arrive at a number of foot-candles (fc). Foot-candles are a unit of light intensity, sometimes more formally called illuminance, and one foot-candle is the illuminance produced by a standard candle one foot away. (Illuminance can also be measured in the SI unit of lux, where 1 fc ≈ 10 lux, but in cinematography foot-candles are more commonly used. It’s important to remember that illuminance is a measure of the light incident to a surface, i.e. the amount of light reaching the subject. It is not to be confused with luminance, which is the amount of light reflected from a surface, or with luminous power, a.k.a. luminous flux, which is the total amount of light emitted from a source.)

Usually you start with a T-stop (or f-stop) that you want to shoot at, based on the depth of field you’d like. You also need to know the ISO and shutter interval (usually 1/48th or 1/50th of a second) you’ll be shooting at. Next you need to convert these facets of exposure into an illuminance value, and there are a few different ways of doing this.

One method is to use a light meter, if you have one, which you enter the ISO and shutter values into. Then you wave it around your office, living room or wherever, pressing the trigger until you happen upon a reading which matches your target f-stop. Then you simply switch your meter into foot-candles mode and read off the number. This method can be a bit of a pain in the neck, especially if – like mine – your meter requires fiddly flipping of dip-switches and additional calculations to get a foot-candles reading out of.

A much simpler method is to consult an exposure table, like the one below, or an exposure calculator, which I’m sure is a thing which must exist, but I’ll be damned if I could find one.

Some cinematographers memorise the fact that 100fc is f/2.8 at ISO 100, and work out other values from that. For example, ISO 400 is four times (two stops) faster than ISO 100, so a quarter of the light is required, i.e. 25fc.

Alternatively, you can use the underlying maths of the above methods. This is unlikely to be necessary in the real world, but for the purposes of this blog it’s instructive to go through the process. The equation is:

where

  • b is the illuminance in fc,
  • f is the f– or T-stop,
  • s is the shutter interval in seconds, and
  • i is the ISO.

Say I’m shooting on an Alexa with a Cooke S4 Mini lens. If I have the lens wide open at T2.8, the camera at its native ISO of 800 and the shutter interval at the UK standard of 1/50th (0.02) of a second…

… so I need about 12fc of light.

 

The right instrument

In the rare event that you’re actually lighting your set with candles – as covered in my Barry Lyndon and Stasis posts – then an illuminance value in fc is all you need. In every other situation, though, you need to figure out which electric light fixtures are going to give you the illuminance you need.

Manufacturers of professional lighting instruments make this quite easy for you, as they all provide data on the illuminance supplied by their products at various differences. For example, if I visit Mole Richardson’s webpage for their 1K Baby-Baby fresnel, I can click on the Performance Data table to see that this fixture will give me the 12fc (in fact slightly more, 15fc) that I required in my Alexa/Cooke example at a distance of 30ft on full flood.

Other manufacturers provide interactive calculators: on ETC’s site you can drag a virtual Source Four back and forth and watch the illuminance read-out change, while Arri offers a free iOS/Android app with similar functionality.

If you need to calculate an illuminance value for a distance not specified by the manufacturer, you can derive it from distances they do specify, by using the Inverse Square Law. However, as I found in my investigatory post about the law, that could be a whole can of worms.

If illuminance data is not available for your light source, then I’m afraid more maths is involved. For example, the room I’m currently in is lit by a bulb that came in a box marked “1,650 lumens”, which is the luminous power. One lumen is one foot-candle per square foot. To find out the illuminance, i.e. how many square feet those lumens are spread over, we imagine those square feet as the area of a sphere with the lamp at the centre, and where the radius r is the distance from the lamp to the subject. So:

where

  • is again the illuminance in fc,
  • is the luminous power of the souce in lumens, and
  • r is the lamp-to-subject distance in feet.

(I apologise for the mix of Imperial and SI units, but this is the reality in the semi-Americanised world of British film production! Also, please note that this equation is for point sources, rather than beams of light like you get from most professional fixtures. See this article on LED Watcher if you really want to get into the detail of that.)

So if I want to shoot that 12fc scene on my Alexa and Cooke S4 Mini under my 1,650 lumen domestic bulb…

… my subject needs to be 3’4″ from the lamp. I whipped out my light meter to check this, and it gave me the target T2.8 at 3’1″ – pretty close!

 

Do I have enough light?

If you’re on a tight budget, it may be less a case of, “What T-stop would I like to shoot at, and what fixture does that require?” and more a case of, “Is the fixture which I can afford bright enough?”

Let’s take a real example from Perplexed Music, a short film I lensed last year. We were shooting on an Alexa at ISO 1600, 1/50th sec shutter, and on Arri/Zeiss Ultra Primes, which have a maximum aperture of T1.9. The largest fixture we had was a 2.5K HMI, and I wanted to be sure that we would have enough light for a couple of night exteriors at a house location.

In reality I turned to an exposure table to find the necessary illuminance, but let’s do the maths using the first equation that we met in this post:

Loading up Arri’s photometrics app, I could see that 2.8fc wasn’t going to be a problem at all, with the 2.5K providing 5fc at the app’s maximum distance of 164ft.

That’s enough for today. All that maths may seem bewildering, but most of it is eliminated by apps and other online calculators in most scenarios, and it’s definitely worth going to the trouble of checking you have enough light before you’re on set with everyone ready to roll!

See also: 6 Ways of Judging Exposure

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How Big a Light do I Need?

Colour Rendering Index

Many light sources we come across today have a CRI rating. Most of us realise that the higher the number, the better the quality of light, but is it really that simple? What exactly is Colour Rendering Index, how is it measured and can we trust it as cinematographers? Let’s find out.

 

What is C.R.I.?

CRI was created in 1965 by the CIE – Commission Internationale de l’Eclairage – the same body responsible for the colour-space diagram we met in my post about How Colour Works. The CIE wanted to define a standard method of measuring and rating the colour-rendering properties of light sources, particularly those which don’t emit a full spectrum of light, like fluorescent tubes which were becoming popular in the sixties. The aim was to meet the needs of architects deciding what kind of lighting to install in factories, supermarkets and the like, with little or no thought given to cinematography.

As we saw in How Colour Works, colour is caused by the absorption of certain wavelengths of light by a surface, and the reflection of others. For this to work properly, the light shining on the surface in the first place needs to consist of all the visible wavelengths. The graphs below shows that daylight indeed consists of a full spectrum, as does incandescent lighting (e.g. tungsten), although its skew to the red end means that white-balancing is necessary to restore the correct proportions of colours to a photographed image. (See my article on Understanding Colour Temperature.)

Fluorescent and LED sources, however, have huge peaks and troughs in their spectral output, with some wavelengths missing completely. If the wavelengths aren’t there to begin with, they can’t reflect off the subject, so the colour of the subject will look wrong.

Analysing the spectrum of a light source to produce graphs like this required expensive equipment, so the CIE devised a simpler method of determining CRI, based on how the source reflected off a set of eight colour patches. These patches were murky pastel shades taken from the Munsell colour wheel (see my Colour Schemes post for more on colour wheels). In 2004, six more-saturated patches were added.

The maths which is used to arrive at a CRI value goes right over my head, but the testing process boils down to this:

  1. Illuminate a patch with daylight (if the source being tested has a correlated colour temperature of 5,000K or above) or incandescent light (if below 5,000K).
  2. Compare the colour of the patch to a colour-space CIE diagram and note the coordinates of the corresponding colour on the diagram.
  3. Now illuminate the patch with the source being tested.
  4. Compare the new colour of the patch to the CIE diagram and note the coordinates of the corresponding colour.
  5. Calculate the distance between the two coordinates, i.e. the difference in colour under the two light sources.
  6. Repeat with the remaining patches and calculate the average difference.

Here are a few CRI ratings gleaned from around the web:

Source CRI
Sodium streetlight -44
Standard fluorescent 50-75
Standard LED 83
LitePanels 1×1 LED 90
Arri HMI 90+
Kino Flo 95
Tungsten 100 (maximum)

 

Problems with C.R.I.

There have been many criticisms of the CRI system. One is that the use of mean averaging results in a lamp with mediocre performance across all the patches scoring the same CRI as a lamp that does terrible rendering of one colour but good rendering of all the others.

Demonstrating the non-continuous spectrum of a fluorescent lamp, versus the continuous spectrum of incandescent, using a prism.

Further criticisms relate to the colour patches themselves. The eight standard patches are low in saturation, making them easier to render accurately than bright colours. An unscrupulous manufacturer could design their lamp to render the test colours well without worrying about the rest of the spectrum.

In practice this all means that CRI ratings sometimes don’t correspond to the evidence of your own eyes. For example, I’d wager that an HMI with a quoted CRI in the low nineties is going to render more natural skin-tones than an LED panel with the same rating.

I prefer to assess the quality of a light source by eye rather than relying on any quoted CRI value. Holding my hand up in front of an LED fixture, I can quickly tell whether the skin tones looks right or not. Unfortunately even this system is flawed.

The fundamental issue is the trichromatic nature of our eyes and of cameras: both work out what colour things are based on sensory input of only red, green and blue. As an analogy, imagine a wall with a number of cracks in it. Imagine that you can only inspect it through an opaque barrier with three slits in it. Through those three slits, the wall may look completely unblemished. The cracks are there, but since they’re not aligned with the slits, you’re not aware of them. And the “slits” of the human eye are not in the same place as the slits of a camera’s sensor, i.e. the respective sensitivities of our long, medium and short cones do not quite match the red, green and blue dyes in the Bayer filters of cameras. Under continuous-spectrum lighting (“smooth wall”) this doesn’t matter, but with non-continuous-spectrum sources (“cracked wall”) it can lead to something looking right to the eye but not on camera, or vice-versa.

 

Conclusion

Given its age and its intended use, it’s not surprising that CRI is a pretty poor indicator of light quality for a modern DP or gaffer. Various alternative systems exist, including GAI (Gamut Area Index) and TLCI (Television Lighting Consistency Index), the latter similar to CRI but introducing a camera into the process rather than relying solely on human observation. The Academy of Motion Picture Arts and Sciences recently invented a system, Spectral Similarity Index (SSI), which involves measuring the source itself with a spectrometer, rather than reflected light. At the time of writing, however, we are still stuck with CRI as the dominant quantitative measure.

So what is the solution? Test, test, test. Take your chosen camera and lens system and shoot some footage with the fixtures in question. For the moment at least, that is the only way to really know what kind of light you’re getting.

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Colour Rendering Index

Know Your Lights: Fluorescent

Unusually being used as practicals, in a music promo, are a 2'x4 Kino Flo (foreground, with 3200K tubes) and a Kino Flo Diva Lite (top left, with 5500K tubes).
Unusually being used as practicals, in a music promo, are a 2’x4 Kino Flo (foreground, with 3200K tubes) and a Kino Flo Diva-Lite (top left, with 5500K tubes).

Tungsten and/or HMI lamps are usually the workhorse units of a lighting package, providing the power that is needed to key-light all but the smallest of set-ups. But they’re not right for every situation. If you don’t need the punch of a point source, and you want something a little softer, fluorescents might be the answer.

This is the third category of lighting units I’m covering in my Know Your Lights series; back up to the overview if you want to start from the beginning.

Fluorescent units use very similar technology to HMIs, with electrodes exciting a gas so that it gives off UV light. The phosphor coating on the tube absorbs the UV light and fluoresces, i.e. re-emits the light in the visible spectrum. Like HMIs, fluorescent units require a ballast to regulate the current.

One of the most notable early uses of fluorescents was in Robocop (1987). Jost Vocano, ASC chose the fixtures because the long, thin reflections looked great on Robocop’s suit. The flip side of that coin is that under certain circumstances fluorescents can make actors’ skin unpleasantly shiny. There was a scene in Ren: The Girl with the Mark where the poor make-up artist had to cake layers of powder onto Sophie Skelton to combat the shine of a Kino Flo I had set up.

Robocop (1987, dir. Paul Verhoeven) - note the fluorescent strips reflected in the suit.
Robocop (1987, dir. Paul Verhoeven) – note the fluorescent strips reflected in the suit.

One way I often use fluorescents is as a “Window Wrap”, a soft source that augments a hard HMI coming in through a window to wrap the light more pleasingly around the talent’s face. Or I’ll place a fluorescent outside the room, to represent or enhance indirect daylight spilling through a doorway.

Being soft sources, the light rays which fluorescents emit spread out widely, meaning the intensity drops off quickly as you move away from the lamp. (We refer to this as “throw”: fluorescents have little throw, whereas spotlights have a lot of throw.) For this reason they start to become pretty ineffective once you get more than about 6ft away from them, depending on the model.

Kino Flo is far and away the most common brand of fluorescent lighting used in the film and TV industry today, so apologies if the rest of this post reads a little like an advert for them. They’re not paying me, honestly!

The company was started by gaffer Frieder Hochheim and best boy Gary Swink after inventing the units for the 1987 comedy-drama Barfly (DP: Robby Müller, BVK). They required a fixture small enough to tuck into little alcoves in a bar location, without getting hot and causing damage.

Kino Flos come in two different kinds:

 

4'x4 Kino Flo with remote ballast leaning against the base of the C-stand
4’x4 Kino Flo with remote ballast leaning against the base of the C-stand
4-bank Kino Flo ballast
4-bank Kino Flo ballast

Remote Ballast

With these units, the lighting fixture is separate to the ballast, and they are connected by a header cable, just like HMIs. Remote units are usually referred to by two numbers, the first representing the length of the tubes in feet, and the second representing the number of tubes. So a unit with two tubes, four feet in length, is called a “4ft 2-bank”, often written as: 4’x2 (pronounced “four by two”).

The most common units are 2’x4 (a.k.a. “fat boy”), 4’x4 and 4’x2, but others are available, including “Single Flo” units and 6ft/8ft “Mega” units.

The ballasts allow you to turn individual tubes on and off as required, and also feature a switch marked either Hi/Lo or 4ft/2ft, which reduces the light output by adjusting the current waveform.

 

Kino Flo Tegra
Kino Flo Tegra. You can see the integrated ballast on the back.

Built-in Ballast

As you might expected, these models combine the fixture and ballast into a single unit. They are designed primarily for interview/ENG applications where it is more convenient to have everything in one. On drama productions it is generally preferable to have a remote fixture, which will be lighter, and a header cable running to an easily accessible ballast.

One advantage of built-in models over their remote cousins is that they are smoothly dimmable down to 5%.

Built-in units are known by names rather than numbers: “Diva-Lite” (2’x4), “Tegra” (4’x4) and “BarFly”, which resembles a swollen 1’x1′ LED panel. There is also the large “Image 87”, a 4’x8 fixture with a built-in ballast. It’s great for lighting green and blue screens because it puts out so much soft light.

Kino Flo Image 87 with a silver egg crate fitted
Kino Flo Image 87 with a silver egg crate fitted
Top to bottom:
Top to bottom: 2900K, 3200K and 5500K tubes

Kino Flo tubes are available in five colours:

  • KF55 – 5500K – i.e. daylight – identified by blue end caps on the tubes
  • KF32 – 3200K – standard tungsten – gold end caps
  • KF29 – 2900K – warm tungsten – red end caps
  • 420nm blue – an extra-saturated blue for lighting blue screens
  • 525nm green – for lighting green screens

Kino Flos often come with plastic grids known as “egg crates” or “louvres”. Their purpose is to make the light more directional, effectively polarising it on a macro scale. They come in black, silver and “honeycomb” varieties, the latter available in 45º, 60º and 90º angles so you can choose how directional the light becomes – and, as a side effect, how much intensity you lose.

It is possible to remove the tubes and wiring from a Kino Flo housing so that the lamps can be squeezed into a tight space. For example, on The Little Mermaid we needed to see a soft blue glow emanating from a small translucent compartment in an organ. Best boy “Captain” Dan Xeller removed a 2ft Kino tube from its housing and placed it inside the compartment, running the wires out the back to the ballast.

Pampa Light in action behind the scenes of Ren: The Girl with the Mark. You can see I've gelled it with Quarter Minus Green in an attempt to correct the CRI.
Pampa Light in action behind the scenes of Ren: The Girl with the Mark. You can see I’ve gelled it with Quarter Minus Green in an attempt to correct the CRI.

Other than Kino Flo, another brand of fluorescent lights you may come across is Pampa Lights. They come in rugged boxes which can be interlinked to create larger banks of illumination. Unfortunately, in my experience the CRI (see overview) is not good, and they are best avoided.

The same goes even more so for the many fluorescent softbox kits available on Ebay from Hong Kong sellers. Not only are they flimsy in construction and questionable in terms of electrical safety, but the CRI of the lamps is very, very poor. If you need a cheap soft source, you would be much better off bouncing a halogen work light off a white card.

Indeed, firing an incandescent source into a bounce board will give you a better quality of light than even a Kino Flo. But a fluorescent fixture won’t make the room unbearably warm, it can emit daylight-balanced light, and it’s quicker to set up than a bounce board and the attendant flags. In a nutshell, it’s more convenient.

Next week, the Know Your Lights series concludes with a look at the fast-evolving world of LED illumination.

Know Your Lights: Fluorescent

Know Your Lights: HMIs

18K bubble for an Arrimax 12/18
18K bubble for an Arrimax 18/12

Following on from last week’s look at tungsten units, today we focus on HMI lighting. HMIs are more complex technology than tungsten, meaning they are far more expensive, and more prone to problems, particularly if you get a deal from a hire company and they give you older units. But they are bright and relatively efficient and because of this, and their colour temperature of 5,600K, they are by far the most popular type of light used in today’s film and TV industry when battling or mixing with natural daylight.

HMIs (hydragyrum medium-arc iodide) operate by creating an arc between two electrodes. This arc excites a gas which produces the light. In order to ignite the arc, a ballast is required. This device also regulates the current, while a special header cable connects the ballast to the light.

Arri_540817_Ballast_Electronic_2500_4000_Watts_1317042538000_325678
Arri electronic ballast for 2.5K and 4K HMIs

Ballasts come in two types: electronic and magnetic. Magnetic ballasts are cheaper, but if you are shooting at a shutter interval out of sync with the cycling of your power supply – e.g. 1/48th of a second with a 50Hz UK power supply – the HMI will appear to flicker on camera. Electronic ballasts have a ‘flicker free mode’ which converts the sine wave of the power supply into a square wave so that the arc does not extinguish at any point in the cycle. A side effect of this is that the head and/or ballast can produce humming, buzzing or squealing noises. Therefore many electronic ballasts have a ‘silent mode’ which reduces the noise but only prevents flicker at standard frame rates, not for high-speed work. In practice, flicker is rarely a problem as the shutter angles of today’s digital cameras can easily be tweaked to deal with it at common frame rates.

Adjusting an Arri Daylight Compact 1200 (a 1.2K MSR) on the set of Ashes. Photo: Sophie Black
Adjusting an Arri Daylight Compact 1.2K HMI fresnel

Like tungsten units, HMIs are available in open face, par and fresnel varieties, though the open face models are not very common. Arri, the major manufacturers of HMIs, call their daylight par fixtures ‘Arrisun’. Other HMI brands include Film Gear, Silver Bullet and K5600, which makes Jokers (see below).

Measured by their wattage, standard HMIs sizes are: 200W, 575W, 1.2K, 2.5K, 4K, 6K, 12K, 18K.

The smaller models, up to 2.5K, are fairly common on no-budget sets, because they can run off a domestic power supply and so don’t require a generator. At the other end of the scale, 18Ks are standard for daylight exterior and interior work on medium budgets and above.

Because of their power, HMIs often play a key part in night exterior lighting too. A 12K or 18K on a condor crane may be used to simulate the moon, while other HMI units, perhaps bounced or coming through a frame, might serve as sidelight or fill. By choosing to shoot at 3,200K, you automatically turn these HMI sources blue, often a desirable look for nighttime work.

Two 18K Silver Bullet HMI fresnels rigged to a condor crane to provide moonlight for a night exterior on The Little Mermaid
Two 18K Silver Bullet HMI fresnels rigged to a condor crane to provide moonlight for a night exterior on The Little Mermaid

There are many variants on the standard HMIs. Here are some of the more common ones.

Arrilux 125W Pocket Par
Arrilux 125W Pocket Par

Pocket pars are little 125W daylight pars that can be run off batteries. Before the days of LED panels, I used one of these for eye-light on a short film set in a forest in daylight. They can also make a good TV gag when bounced off a wobbling silver reflector.

K5600 Joker Bug 800W
K5600 Joker Bug 800W

Jokers are small units that come in 400W and 800W models. They can be reconfigured in various ways and even slotted into Source 4 housings (see last week’s tungsten post) to convert these units to daylight. We used a 400W joker a couple of times on Heretiks, when there was little space to rig in but we needed a fair bit of punch – like daylight through a small window.

Arrimax M18
Arrimax M18

The Arrimax range uses a hybrid of par and fresnel technology. They are lighter and more efficient than standard HMIs – the 800W model puts out almost as much light as an ordinary 1.2K, for example – but they’re more expensive to hire and don’t create the nice shafts of light that some DPs like (ahem). The model numbers are the wattage in tenths of a kilowatt: M8 (800W), M18 (1.8K), M40 (4K), M90 (9K) and the anomalously-named Arrimax 18/12 which accepts both 12K and 18K bubbles.

Airstar helium balloons in action
Airstar helium balloons in action

Helium Balloons are designed to provide a soft overhead illumination for night exteriors or high-ceilinged interiors. They come in a range of shapes and sizes, and aren’t necessarily HMIs; they can be fitted with tungsten lamps, or a combination of both.

Again, please let me know on Facebook or Twitter if I’ve missed out any of your favourite units. Next week: fluorescents.

Know Your Lights: HMIs

Know Your Lights: Tungsten

Following on from my ‘Know Your Lights’ overview last week, today I’ll look in more detail at the first category of lamps and the various units available and when you might use them.

And that first category is incandescent lighting, commonly known as tungsten. It is the oldest, simplest and most robust lighting technology. Tungsten lamps are the cheapest to hire, the easiest to repair, and emit a smoother spectrum of light than any other artificial sources, making for the most natural skin tones. For my money, there’s no better way to artificially light a human face than by bouncing a tungsten source off polyboard.

This comparison of domestic bulbs against daylight shows the spectra of light they emit.
This comparison of domestic bulbs against daylight shows the spectra of light they emit, with incandescent (tungsten) and halogen producing the smoothest spectra of the artificial sources.

Tungsten lighting units can be sub-categorised by the style of reflectors and/or lenses in the heads…

 

Open-face

Lilliput 300W open-face lamp
Ianiro Lilliput, a 300W open-face light

Redheads draw 800W each
Generic 800W open-face light

Unknown
Arrilite 1000, a 1K open-face light

A blonde - a basic 2,000W tungsten lamp
Generic 2K open-face light

The simplest instruments are known as ‘open-face’ because they have no lens to focus the light. By far the most common units are the 800 Watt and 2,000 Watt models. These are often referred to as ‘redheads’ and ‘blondes’ respectively, though I strongly discourage these terms for reasons touched on here. 300W models – dubbed ‘Lilliputs’ by manufacturer Ianiro – are also available, as well as 1Ks and much larger models like the Mole-Richardson Skypan 5K and Skylite 10K.

While I have lit entire no-budget features with just open-face lights, on larger productions the uneven and unfocused nature of their light makes them a poor relation of other units on the truck. They are most likely to get fired into a bounce board or used to create a little pool of light somewhere in the deep background where finesse is not needed.

 

Fresnel

Arri 300W fresnel
Arri 300W fresnel

Filmgear 650W fresnel
Filmgear 650W fresnel

Mole Richardson 1K 'baby' fresnel
Mole Richardson 1K ‘baby’ fresnel

Arri T12, a 12K fresnel
Arri T12, a 12K fresnel

The fresnel lens was invented in the early 19th century by French physicist and engineer Augustin-Jean Fresnel in order to increase the focus and throw of lighthouse lamps. Today in the film industry, fresnel lenses can be found on tungsten, HMI and even LED fixtures.

Fresnel lens
Fresnel lens

Tungsten fresnels come in the following wattages: 150W, 300W, 650W (a.k.a. ‘tweenie’), 1K, 2K, 5K, 10K, 12K, 20K, 24K.

1Ks and 2Ks are sometimes called ‘babies’ and ‘juniors’ respectively, but confusingly those terms can also refer to whether they are the smaller location models or larger studio versions of the same wattage.

Though the fresnel lens reduces the light output a little, the beam is much more focused and can therefore create a shaft of light through smoke, which open-face lamps cannot. Hence I sometimes use tungsten fresnels to simulate hard sunlight when shooting on a stage. But beware that shadows cast by a fresnel can sometimes show up the ridges in the lens.

I often fire fresnels into bounce boards, and because their light is more focused they require less flagging to control the spill than open-face units.

On Heretiks we used numerous 300W and 650W fresnels to beef up candlelight, often placing tough-spun diffuser over them, dimming them down to warm up the colour temperature, and flickering them too.

 

Par (parabolic aluminised reflector)

Par 16 (birdie)
Par 16 (birdie)

Par 38
Par 38

Filmgear 4-light Minibrute
Filmgear 4-light minibrute

Mole Richardson 9-light maxibrute
Mole Richardson 9-light maxibrute

Par lights use a parabolic (shaped like half a rugby ball) reflector and a lens to produce a soft-edged oval pool of light. They are extremely common in theatres, but are often used in film and TV as well.

Unlike fresnel and open-face units, par cans are referred to not by wattage but by the diameter of the bubble in eighths of an inch. So a Par 16 (a.k.a. ‘birdie’) has a 2″ bulb.

Par cans come in the following sizes: 16, 20, 36, 38, 46, 56, 64. They also come with various internal specs which affect the width of the beam.

Par cans are good for throwing shafts of light. On The Little Mermaid I used them to simulate car headlights, and as practicals (i.e. they were seen on camera) to uplight banners at the circus.

Maxibrutes (a.k.a. ‘Molepars’) are banks of multiple par 64 (1KW) lights. They come in banks of 4, 6, 9, 12 or 24. They pop up in the background of music promos quite often, because they look cool and kind of retro. I used two 9-light Maxibrutes, bounced off the tent roof, to illuminate the big top in The Little Mermaid. Some DPs like to use Maxibrutes for backlight on night exteriors. If you’re using them direct, you’ll need at least a sheet of diff to prevent multiple shadows.

Minibrutes (a.k.a. ‘fays’) are similar, but use smaller par 36 (650W) lamps.

 

Other

Dedo, de-e-edo. Dedo come and me want go home.
Dedolite

Dedolites are compact units that use a unique lens system to produce very focussed, controllable light from (most commonly) 150W bulbs. They are widely available to hire, come with in-line dimmers, and are small and light enough to be rigged overhead or in tight spots. I often use them to beef up practicals.

ETC Source Four
ETC Source Four

Source Fours or (a.k.a. ‘lekos’) are ellipsoid reflector spotlights. They feature cutters which can be used to shape the beam, they can be hired with different lenses (some of which are zoomable), and they can be fitted with gobos to project patterns. They are good for stylised pools of light or for firing into distant bounce boards without spilling light elsewhere.

Spacelights
Spacelights

Spacelights are wagon-wheel configurations of three or six 1K lamps inside a cylinder of diffusion material. They are normally used in large numbers to provide ambient toplight on stage. Click here for a brief video introduction to spacelights.

1K Jem ball
1K Jem ball

Jem Balls, or China balls, resemble Chinese paper lanterns. They come in 22″ (up to 1KW) and 30″ (up to 2KW) sizes and produce a very soft light which I personally find is never bright enough.

Bare bulbs (usually referred to as ‘globes‘) in pendant fittings can be hung from overhead or hidden behind set dressing, perhaps to beef up practicals. On Ren: The Girl with the Mark and other projects I hid some globes behind furniture to enhance the pool of light from candles.

Finally, tungsten is usually the most desirable type of bulb to use in practicals. It is commonplace when shooting a daylight interior for a spark to go around replacing the energy-saver fluorescent bulbs in the table lamps with old-school tungsten ones. The colour is much nicer, the skin tones are better as noted above, and they can be dimmed to just the right level for camera.

 

I’m sure I’ve missed something out – please feel free to let me know on Facebook or Twitter! Next week: HMIs.

Know Your Lights: Tungsten

Top Tips from Day One of the Big League Cine Summit 2015

blcs-blue-on-whiteThis week the third annual Big League Cine Summit is taking place: two days of online masterclasses with top commercial, TV and feature film cinematographers. If you missed this educational and inspirational free event, here are the best tips I culled from day one’s sessions:

Frankie DeMarco – “Composition and Camera Operating for the Big Screen”

  • The advantage for a DP of working with a separate camera op is that you have a second opinion.
  • Try to think like an editor. What specific shots do you need to tell the story? Can you do it in a “oner”?
  • Lots of angles/coverage can kill performances and make the audience overly aware of the camera.
  • If you need to shift position for comfort, do it during a part of the take that the editor is unlikely to use.
  • You can sometimes get away with crossing the line if your singles are dirty.
  • Use clean singles to show that characters are not connecting with each other.
  • Single point perspective, a.k.a. formal composition (framing the subject centrally) can be very powerful.
  • Lighting for silhouette can make a simple moment highly evocative.
  • The best composition reflects character relationships, perhaps using layers and depth.
  • Good composition should draw the eye to the right part of the screen and not distract the audience.
  • Good cinematography should tap into the emotion of the scene and the character whose eyes we’re seeing it through.
  • When watching the blocking, think about the emotions. Let the scene tell you how it should be shot.
  • Let the lens talk to you. Try watching the blocking through different lenses and see what feels right.
  • A great static frame that the actor can move around in trumps panning around with the actor.
  • Use a dolly-in for an emotional moment, but a zoom-in to show a character having a thought or idea.
  • Check out Stanley Kubrick and William Friedkin films to see excellent use of zooms.
  • Use a long lens to disconnect your subject from their surroundings.
  • Play the first take safe, and then you can try tagging hand-props or pulling focus to background characters on later takes.
  • “When in doubt, turn it out.” i.e. beware of over-lighting!
  • Don’t be afraid of changing f-stops from angle to angle to maintain a consistent softness of background when your background is different distances away from different subjects.
  • Don’t worry about continuity too much. “The set is made of rubber.”
  • Try unusual compositions. Be willing to fail.

Kevin Shahinian – “Story Telling Techniques: Adding Massive Production Value”

  • In high-end events shooting, try to get the organisers to pick rooms that will work for sun orientation.
  • Use a long lens to create a potentially unsettling sense of voyeurism.
  • To build tension and unsettle the audience, short-side your subject and show lots of empty background.
  • In an over-the-shoulder shot, add power to the foreground character by having them dominate the frame.
  • With non-actors, shoot candid footage; you may capture genuinely great moments. Use action verbs to direct them, rather than talking in terms of emotions.

Rasmus Heise – “Extraordinary Cinematography with Minimal Lighting”

  • Design lighting that works from all directions, to minimise set-up times.
  • Use more than one colour to add depth.
  • Dot practicals around where possible, to give you sources that will work for different angles.
  • Focus on one key light source in a scene. Everything else is just a bonus.
  • Fluorescent tubes and sodium vapour lamps can be great low budget, low wattage solutions.
  • Philips makes fluorescent tubes with high CRI.
  • Wet down your exterior sets to add contrast and nice reflections.
  • Silhouette shots are quick, cheap and look great.

Matthew Santo – “Commercial Lighting: How to Light Fashion vs. Action”

  • Photographing commercials is all about heightened reality, perfect sunsets, perfect skin, etc.
  • It requires a lot of passive lighting: bounce cards, negative fill, contrast control.
  • On beauty and fashion commercials:
    • Your background can set a darker mood even if the talent has to be lit flatly for beauty.
    • Know your talent’s face in advance – e.g. do they have soft or hard features? Deep-set eyes?
    • What side is the talent’s hair parted on? This could affect your decision on which side to key from.
    • Try to make sure the make-up room’s lighting matches the colour of your lighting on set, so the MUA doesn’t get any nasty surprises on set.
    • Use Briese lights for beauty. They have hard- and softlight qualities.
    • Chimeras may be better for talent with less defined features.
    • Reduce skin texture by pushing fill through large frames or bounce, e.g. 12×12 frames.
    • Hard backlight looks great but beware of fly-away hair.
    • Combine hard and soft sources for backlight that has punch but wraps and doesn’t create shadow issues.
    • There’s a range of Cosmetic lighting gels that add a little warmth and diffusion.
    • Use a low overall light level for talent comfort and less squinting!
  • On sport and action commercials:
    • It’s about movement and body definition. Backlight and sidelight are most important.
    • Edgelight defines the talent’s body shape. Toplight adds muscle definition.
    • Lens flares add dynamism but reduce contrast, so light high-key.
    • Use higher light levels for highspeed shooting and to maintain focus as people move.

Stefan V. Borbely – “Deconstructing High End Car Commercials”

  • Rather than lighting the car, light the environment and the car will reflect that environment.
  • For exteriors, wait for dramatic skies because the car will reflect these.
  • Silver cars are the easiest to light.
  • Use long fluorescent tubes or long reflectors to make seamless long highlights on the bodywork.
  • Use Cinema 4D to test your lighting set-ups for reflections.
  • For night exteriors, take stills on the recce and note your exposure settings.
  • Bagolights are great for creating streaks of light on cars.
  • Fisherlights are a good substitute for the sky.
  • If you can’t afford Fisherlights overhead, put lamps on the floor and shoot them up into big polyboards.
  • Schedule your exterior shots for sunrise and sunset, and shoot inside the car in the middle of the day.

There is still time to get free access to the summit at bigleaguecinesummit.com Stay tuned to neiloseman.com for top tips from day two.

 

Top Tips from Day One of the Big League Cine Summit 2015

Lighting Droplets

The tarsier puppet in Droplets
The tarsier puppet in Droplets

Lighting in the controlled environment of a studio should theoretically be much easier than lighting a location, but I found recently that it doesn’t come without its challenges.

Last month I had the pleasure of working on a music promo for Droplets by Lewis Watson and Gabrielle Aplin. Directed by Tom Walsh and designed by First Musketeer veteran Amy Nicholson, this magical, handmade puppet fest was only the second or third studio-bound production of my career. Tom had secured the use of Giltbrook Studios, an impressively equipped 1,300 sq ft soundstage in Nottingham, complete with manager Andy Swain as gaffer.

Apart from the exclusion of pesky natural light, the biggest advantage offered by a stage over a location is the lighting grid; no more wondering if that polecat or K-clamp will take the paint off the wall, and no more compromising your backlight position to keep the stand out of frame. The downside of the grid is the time it takes to rig or adjust a light, particularly if the grid, like Giltbrook’s, has no catwalks, and every adjustment must be made by bringing in and scaling a huge ladder. In fact it may be impossible to rig or adjust lights once there is a finished set underneath. All of which means you’re going to need a pre-rig day.

Some of the ill-fated space lights can be seen here, as well as the cucoloris rigged beneath the 650W fresnel key light. At the top left is the 2K fresnel backlight.
Some of the ill-fated space lights can be seen here, as well as the cucoloris rigged beneath the 650W fresnel key light. At the top left is the 2K fresnel backlight.

In the case of Droplets, the pre-rig day was also used to assemble the set, a tree on top of a cave, which must have measured about fifteen feet in height. As soon as it had been erected we realised that the six space lights Andy had spent all morning rigging were going to be in frame, as the top of the tree reached above the bottoms of these lights. (A space light is a circular arrangement of six tungsten tubes inside a cylinder of white diffusion cloth. They’re typically used in large numbers to simulate daylight in a studio.)

Some of the par cans that supplied the colour wash on the backdrop.
Some of the par cans that supplied the colour wash on the backdrop.

In fact my options on where I could put lights were very narrow, because of the lack of space around the set, both vertically and horizontally. We shot against the studio’s white infinity cove, and Tom wanted colour washes over this to suggest various times of day. Andy achieved this with gelled par cans off to either side of the set, but then it was crucial that no other light spilled onto the backdrop or it would ruin the effect.

We rigged a 2K tungsten fresnel immediately behind and above the set, for backlight, but it was hard to put anything in from the sides or the front without contaminating the backdrop. The 650W key light had to be rigged almost directly above the set, and even then its shadow can be seen on the floor in the wide shots if you look carefully. We hung a cucoloris (sheet of wood with random shapes cut in it) below the 650 to created the dappled effect of woodland light, taking care that a patch of light fell on the tarsier puppet’s main position.

For fill I used an LED panel off to the right of the set, dimming it to find a balance between its light being barely visible on the backdrop while still lifting the set and the puppets enough. I placed a smaller LED panel inside the cave, with a turquoise gel to suggest phosphorescence.

The final day/sunset look. From each side an orange-gelled and a pink-gelled par can light the backdrop. A 2K tungsten fresnel provides backlight, while a 650W fresnel with a cucoloris provides dappled light on the tree and tarsier. An LED panel off right supplies fill, and a second panel is inside the cave with a turquoise gel.
The final day/sunset look. From each side an orange-gelled and a pink-gelled par can light the backdrop. A 2K tungsten fresnel provides backlight, while a 650W fresnel with a cucoloris provides dappled light on the tree and tarsier. An LED panel off right supplies fill, and a second panel is inside the cave with a turquoise gel.
For closer shots, a reflector below frame and/or a Dedolight behind camera were used to fill in unwanted shadows.
For closer shots, a reflector below frame and/or a Dedolight behind camera were used to fill in unwanted shadows.

Another advantage of a studio is that you can easily run all the lamps into a dimmer board. This was very handy for Droplets because in addition to the day/sunset look, we had nighttime scenes and a storm to light for, and some on-screen transitions between the states. We were able to set these all up in advance and switch between them pretty much by just pushing a few sliders up and a few others down.

The night state involved a yellow-gelled redhead on the floor behind the cave, pointed straight at the backdrop. With its barn doors removed, this created a circle of light which reminded me strongly of the huge yellow moon in the posters for The Nightmare Before Christmas. I hadn’t been intending to create such a defined circle, but when I saw it I immediately loved its stylised look.

A second 650W fresnel was rigged, close to the first, and with ulcered black wrap in front of it to again created a dappled look, but with a purple gel on it. This took us away from the more traditional blue of nighttime scenes, adding to the stylised look again, and contrasting nicely in colour with the yellow “moon”.

The 2K backlight remained on for the night scenes, but the sunset colour wash on the backdrop was switched off, as was the fill.

Nighttime in puppet land: the 2K backlight remains on, a yellow-gelled redhead lights the backdrop from behind the set, and a purple-gelled 650W fresnel in the grid pushes through a cucoloris to highlight the tarsier.
Nighttime in puppet land: the 2K backlight remains on, a yellow-gelled redhead lights the backdrop from behind the set, and a purple-gelled 650W fresnel in the grid pushes through a cucoloris to highlight the tarsier.

For the storm scene we experimented with strobes, but they caused unpleasant rolling shutter artefacts. Instead I used the flash button on the 2K’s dimmer box to create lightning. Both 650W fresnels were turned off for this state, but the fill was turned back on. While the pink colour wash remained off, we brought up the orange wash just a little bit to suggest an angry sky in the background.

Stormy weather. The orange colour wash coming from the par cans, originally set up for the sunset look, is used here much more dimly to suggest an angry sky. The LED panel off right supplies fill while the 2K backlight is flashed periodically.
Stormy weather. The orange colour wash coming from the par cans, originally set up for the sunset look, is used here much more dimly to suggest an angry sky. The LED panel off right supplies fill while the 2K backlight is flashed periodically.

Copious smoke was used throughout (another advantage of studios – your smoke stays put!) to generate god rays as the backlight streamed through the tree. It also helped soften the backdrop and render the colour washes more convincing as a sky.

Watch the video here. Shot on a Red Epic operated by Chris Wetton. Big thanks to Andy and Giltbrook Studios for all their help. Visit www.polymathematics.co.uk to find out more about the amazing work of Tom Walsh and Amy Nicholson.

Lighting Droplets