T351 Week 6 - Spring 2008

Agenda:

• Projects Update/Reality Check
• Lighting

Project Reality Check

• Interview / feature story: If not turned in already, your pre-production work is due this week in lab. (Proposal and a list of questions.) You'll shoot and edit them next week. We'll let you make teams in lab if you'd like this week. Before you come to lab this week, see when your interview subject is available. It'll make things easier if your subjects are available during your regularly scheduled lab. Interview exercise criteria can all be found on-line in the T351 index.
  • There are downloadable talent release forms you can use on the class web site.
• We'll watch the Audio/News/Reflector pieces this week in lab.
• Your Art Video project ideas are due next week. You should turn in a proposal which will include a treatment and your approach to the content.
• Please also think about your short stories / dramatic scenes. The pre-production materials for the scene are due in two weeks.
• You should also be planning your final project script.

Lighting

Lighting can be thought of in terms of

• Quality (coherence) hard vs. soft
• Color temperature (color)
• Intensity

Quality (coherence)

Lighting instruments can be broken down into two major types: spotlights and floodlights. In general, spotlights produce focused beams of light (hard light) whereas floodlights create softer, more diffused light.

Hard light vs soft light

• Hard lighting creates shadows and brings out texture
• Soft lighting minimizes shadows and details.

For most interview setups, soft lighting produces more pleasing results than hard lighting.

Spotlights:

3 basic types: Fresnel, Ellipsoidal, & Open faced

Fresnel - usually ranked by wattage of lamp. Fresnel spotlights use fresnel lenses- these glass lenses have an easily indentifiable series of coencentric rings cut into them to focus the light.

Ellipsoidal - much more directional/focusable than typical fresnel spotlights. Examples include:

• Pattern projectors
• Follow spots

Open faced - In open faced lighting instruments, the lamp is housed in front of a reflector, but there is no lens to focus the light. The Lowell Omni and Tota lights are good examples of open faced spotlights. Lighting people directly with open faced lamps usually looks terrible. The best way to deal with open faced lights is to use an umbrella or a diffuser of some sort.

Types of lamps:

• Incandescent: These bulbs are larger than quartz bulbs. These are like the typical screw-in bulbs we use at home. They become redder with age.
• Quartz or Tungsten Halogen: encased in a quartz bulb with halogen gas. Smaller & retains its color temp. Don’t ever touch with bare fingers! It will put oil on the surface and reduce the life span.
• Fluorescent: can be almost any color temp (kinda sorta) looks green. They work well when mixed with other light

Floodlights generally produce softer light than spotlights. Examples include:

• Scoops: they look like ice cream scoopers
• Softlights: my favorite to use as a key light! Chimera, Riffa lights. Many softlights mount over a spotlight (turning it into a soft light).
• Broad light: Brighter than a softlight- same idea. Shadows are more defined due to the more focused output.
• Fluorescent light bank: Operates at a cooler temperature compared to incadescents. Can be set up for any color temp Way cheaper than an HMI. Physically, they are shallow (only 6 inches deep or so) so can be placed in tight locations.
• Strip/cyc lights: Used to light cycs. Good for overall even illumination. Often found in theatres and not in video lighting.

Color temperature

We measure color temperature on the Kelvin scale

Indoor vs. outdoors (approximate color temps)

• 3200 degreees Kelvin - indoor color temp
• 5600 degreees Kelvin - outdoor color temp

Remember that the outdoor color temperature varies throughout day.

HMIs: Hydrargyrum Medium Arc. It's too hard to say so people call them HMIs. HMIs are much more expensive than typical spotlights and are used for outdoor lighting. Sometimes called sun guns, they have the same color temp as the sun. (around 5600 degrees Kelvin)

Intensity

We measure intensity in lux or foot-candles.

Lux (European) vs. foot-candle aka lumen (American).

• A lux is the amount of light that falls on the surface of a square meter using a candle as a light source burning one meter away
• A foot-candle is the amount of light that falls on the surface of a square foot using a candle as a light source burning one foot away
  The inverse square law states that for every foot you move away from a light source, your intensity will drop off by 1/4

10.75 Lux = 1 foot-candle

Incident vs reflected light

• Incident light: the light falling on a subject or performance area
• Reflected light: the amount of light bouncing off or reflected from your subject

Light meters give us objective & accurate means of determining light intensity. Using a light meter. Point toward subject to measure reflected light. Point towards light source to measure incident light.

Base light: the minimum operating light level

Lighting Control

You can think of controlling light in three parameters:

• Quality (hard or soft)
• Intensity controls (control brightness)
• Area/Directional Control (How much area we're lighting)

It's important to be able to control one parameter without affecting another. For instance we might want to adjust intensity without affecting quality. Say we want to light our subject with hard light, but just need to lower the output. We shouldn't use a diffuser as it would change the light from hard to soft. So as you choose a method to control or shape the light, be aware of how it affects the other parameters.

Ways to control light:

• Placement - Don't forget that placement is directly related to intensity. Move the light further away to reduce the intensity, closer to increase intensity.
• Dimmers - Good dimmers are expensive, but provide an easy way to control intensity. Cheap (inexpensive) dimmers may create audio interference. Variable transformers generally are more expensive, but don't create as much RF noise.
• Gels - Gels come in many colors as well as neutral density (ND). They reduce the lamp's output without affecting quality.
• Scrims - These small screens fit into the lamp's filter holder. You can use a half scrim to block off a portion of the light. Scrims reduce light output without affecting the quality too much.
• Screens/net/mesh - These are often used behind subjects or over windows in order to reduce the intensity.
• Barn doors. Helps control light spill. Stops back light from hitting camera lens & causing lens flare
• Flags - Flags come in many sizes (2x2, 2x4, etc.) and can be clamped to light stands. Flags can contain reflective or diffusion material or can be completely opaque.
• Diffusers - Typically a fabric-like material that can be placed onto a lamp (like a gel) or suspended in a flag or screen. Diffusion softens and reduces the light output.
• Reflectors - Reflectors bounce light onto the subject from an existing light source. Often used to provide a soft fill and can minimize shadows. White, silver and gold are common colors. A sheet of foam core works well as an inexpensive reflector. Glue tinfoil to one side for more lighting options.

Jim's general tips for lighting interviews in the field -----------

For starters try to find a quiet and large room with no windows (or windows you can block off). Make sure it's large enough that you can set up multiple lights and move them around.

Make sure you can place your subject at least 6-8 feet from the background. The further the better.  If your subject is sitting right next to the background, your key light will hit the wall. If the wall is light, it will look terrible. So make sure there is as much room as possible between the subject and the backround. If you want to see background elements, (pictures, flags, awards, interesting objects, etc) you'll want to be able to light them separately.

It's also nice to be able to place your camera quite a distance from the subject. This is so you can use a longer focal length, and throw the background elements slightly out of focus. This is why large, windowless rooms are perfect.

For general interview setups, I suggest NOT using the subject's office. Offices are usually too small and cluttered. In addition it can take 30-60 minutes to setup audio and lights for a simple, professional-looking interview. It's an inconvenience to your subject and usually makes the videographer feel rushed.

You should also be familiar with the Lighting Triangle:

• Key - illuminates the basic shape of the subject
• Fill - Reduces and fills in shadows created by the key.
• Back -helps separate the subject from the background, creates a figure-ground relationship.
• Background/Set - Lights setting/location. Sets mood and locale of scene.

Key light - For shooting most interviews, soft lighting typically produces more pleasing results than hard lighting. I recommend using either a softbox or an umbrella for your key light. Don't point an open face light at your subject - it looks terrible. A fresnel however can give pleasing results. I usually start by placing the key light a little higher that the camera/interviewer. If your subject is wearing glasses you may have to position the key light higher than normal to reduce the reflection.

Placing the keylight: Broad vs Narrow lighting

Consider if you want broad or narrow lighting. Most interviews are shot portrait style- where the talent is slightly askew from the camera, typically facing an off-camera interviewer.

Broad lighting is when you position the key light on the camera side of the interviewee's primary vector. Narrow (also known as short) lighting is when you place the key light on the other side of the primary vector.

 

Fill - If you're using soft key light, a reflector works fine for fill and is easily controllable. You can adjust the fill amount easily by placement of the reflector and whether you use the white or silver side. (You'll need a stand and spring clips to hold it.)

Back light - A little back light goes a long way. I find I'm always using both gels and diffusion to make it look right. (Try turning off your key light to focus and set your backlight.) This is a good light to use colored gels on.

Set light - Highlighting a special something in the background will add the finishing touch. This is also a good place to use colored gels. Remember to throw the background out of focus a little by using either or both: a small f-stop and a telephoto lens.

 

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