LIGHTING - PowerPoint PPT Presentation

1 / 13
About This Presentation
Title:

LIGHTING

Description:

Professional lighting kits for video and photography are very expensive. ... A professional-level instrument which measures the spectrum of light. ... – PowerPoint PPT presentation

Number of Views:58
Avg rating:3.0/5.0
Slides: 14
Provided by: sdn3
Category:

less

Transcript and Presenter's Notes

Title: LIGHTING


1
LIGHTING
2
Lighting with Background Windows Shooting
pictures indoors with external windows is a
common issue for photographers and video makers.
The large difference in light levels between the
room and the outside view make finding the
correct exposure a challenge. Video is
particularly susceptible to this problem due to
it's relatively low contrast ratio. If you can't
avoid having the window in shot, in most cases
the only thing you can do is use the manual iris
to set your exposure correctly for the subjects
in the room. This means that the window will be
over-exposed but that's a necessary compromise.
If you wish to show the outside view, expose the
iris for the window (which will make the room
dark). Increase the Lighting in the Room Any
extra light you can shine on the subject will
decrease the contrast ratio between them and the
window. In some cases switching on the standard
room lighting can help, although this often
introduces new problems such as clashing colour
temperatures and harsh downward shadows. It's
possible that a reflector board could be
useful. Reduce the Light from the Window You
can reduce the amount of light coming through the
window by placing some sort of filter over it. If
the entire window needs to be in shot you'll need
to be careful and discreet with the scrim/filter.
It can be difficult getting exactly the right
fit. If only part of the window is in shot it's a
lot easier. Filters can cause unwanted side
effects such as ripple and the moire effect.
Being further away from the window helps.
3
Lighting with Background Windows Increase the
Lighting in the Room Reduce the Light from the
Window
4
Reflector Board Sometimes referred to as a
"flecky board", this is a specially-designed
reflective surface which is usually used to act
as a secondary light source. It is particularly
useful as a fill light when working in strong
sunlight. Reflector boards come in white, silver
or gold surfaces. Many reflectors have a
different type of surface on each side, giving
you two lighting options. Gold surfaces provide a
warmer look than silver or white. If you don't
have a reflector board you can improvise. Almost
any suitably-sized object with a reflective
surface will do. Some examples How to Fold Up a
Reflector Board Reflector boards are lightweight
and flexible, and are normally folded up for
transport in a small carry-case. They can be
tricky to fold up if you've never done it you
may want to read the instructions below and
practice in private before having to do it in
front of the whole crew!
5
Contrast Ratio for Televisions
Monitors Contrast Ratio is a specification given
with most good televisions and monitors. It
refers to the device's ability to reproduce
different levels of brightness. A higher
contrast ratio is more desirable 5001 is quite
good. Unfortunately the contrast ratio
specification given by TV manufacturers has
become somewhat abused. There is a limit beyond
which this specification loses significance, as
further improvements aren't noticeable in the
real world. Do not be too concerned with figures
higher than 20001, and figures over 10,0001
don't have much relevance at all. Note
Monitors also vary in their ability to display
levels of gray, i.e. their grayscale performance.
This can also effect the detail in darker areas
of the image.
6
The Standard 3-Point Lighting Technique The
Three Point Lighting Technique is a standard
method used in visual media such as video, film,
still photography and computer-generated imagery.
It is a simple but versatile system which forms
the basis of most lighting. Once you understand
three point lighting you are well on the way to
understanding all lighting. The technique uses
three lights called the key light, fill light and
back light. Naturally you will need three lights
to utilise the technique fully, but the
principles are still important even if you only
use one or two lights. As a rule Key
Light This is the main light. It is usually the
strongest and has the most influence on the look
of the scene. It is placed to one side of the
camera/subject so that this side is well lit and
the other side has some shadow. Fill Light This
is the secondary light and is placed on the
opposite side of the key light. It is used to
fill the shadows created by the key. The fill
will usually be softer and less bright than the
key. To acheive this, you could move the light
further away or use some spun. You might also
want to set the fill light to more of a flood
than the key. Back Light The back light is
placed behind the subject and lights it from the
rear. Rather than providing direct lighting (like
the key and fill), its purpose is to provide
definition and subtle highlights around the
subject's outlines. This helps separate the
subject from the background and provide a
three-dimensional look. If you have a fourth
light, you could use it to light the background
of the entire scene.
7
Measuring Light There are many different units
for measuring light and it can get very
complicated. Here are a few common measurement
terms Candela (cd)Unit of luminous intensity
of a light source in a specific direction. Also
called candle.Technically, the radiation
intensity in a perpendicular direction of a
surface of 1/600000 square metre of a black body
at the temperature of solidification platinum
under a pressure of 101,325 newtons per square
metre. Footcandle (fc or ftc)Unit of light
intensity, measured in lumens per square foot.
The brightness of one candle at a distance of one
foot. Approximately 10.7639 lux. Lumen (lm)Unit
of light flow or luminous flux. The output of
artificial lights can be measured in lumens. Lux
(lx)Unit of illumination equal to one lumen per
square metre. The metric equivalent of
foot-candles (one lux equals 0.0929 footcandles).
Also called metre-candle.
8
Lighting For Video Television Light
Sources All video uses some sort of lighting,
whether it be natural light (from the sun) or
artificial lights. The goal of video lighting is
to choose the best source(s) to achieve your
goals. First and foremost you need enough light.
You must ensure that your camera is able to
record an acceptable picture in the conditions.
With modern cameras this is seldom a problem
except in very low light or strong contrast.
colour temperature white balance Contrast
Ratio Contrast ratio is the difference in
brightness between the brightest and darkest
parts of the picture. Video does not cope with
extreme contrast as well as film, and nowhere
near as well as the human eye. The result of
over-contrast is that some parts of the picture
will be too bright or too dark to see any detail.
For this reason you need to ensure that there is
not too much contrast in your shot.
Camera-Mounted Lights The camera-mounted light
is an easy, versatile solution used by amateurs
and professionals alike. Typically the light will
draw power from the camera battery, although a
separate power supply can be used. Be aware that
lights which draw power from the camera battery
will significantly shorten the battery's charge
time. This type of lighting does not create
pleasing effects. it is a "blunt instrument"
approach which is really only designed to
illuminate the scene enough to allow normal
camera operations. However it is a simple,
practical solution. Night-Mode Video
Shooting Some cameras offer a special "night
vision" option which allows you to shoot with
virtually no light. This mode uses infrared light
instead of normal visible light. This is useful
in extreme circumstances when you have no other
option. Unfortunately the results tend to be
poor-quality monochrome green.
9
Lighting Effects Cold / Warm You can add to the
feeling of coldness or warmth by using additional
filters or doubling up on gels. Very blue means
very cold, very red/orange means very hot.
Moonlight (or any night-time light) This is an
old standard technique which has become something
of a cliché. You can make daytime seem like night
by lowering the exposure slightly and adding a
blue filter to the camera. However a convincing
illusion may require more effort than this you
don't want any daytime giveaways such as birds
flying through shot. You also need to think about
any other lighting which should appear in shot,
such as house or street lights. Firelight To
light a person's face as if they were looking at
a fire, try this Point a redhead with orange gel
away from the subject at a large reflector which
reflects the light back at the subject. Shake the
reflector to simulate firelight (remember to add
sound effects as well). Watching TV To light a
person's face as if they were watching TV, shine
a blue light at the subject and wave a piece of
cloth or paper in front of the light to simulate
flickering.
10
  • DIY Lighting Kit
  • Professional lighting kits for video and
    photography are very expensive. Fortunately for
    the budget-impaired enthusiast, it is possible to
    put together a perfectly adequate lighting kit
    for less than US100.
  • A good beginner's lighting kit should include
  • Three (or more) lights with stands
  • Reflector board(s)
  • Power cables, extension leads and a multi-box.
  • halogen work lamp
  • Reflectors
  • Power
  • Safety

11
Lighting Equipment 18 Gray Card A gray-coloured
card which reflects 18 of the light which falls
upon it. Used as a reference to calibrate light
meters and set exposure. Ballast A device used
to control the electrical current in a light.
  Consoles Hardware and software systems which
control lighting. Operated by the lighting
technician, consoles coordinate lighting displays
on stages, studios, etc. Light Meter A tool used
to measure light and indicate the ideal exposure
setting. Also known as an exposure meter.
12
Lighting Equipment Reflector Board A
specially-designed reflective surface used to act
as a secondary light source. The board is
lightweight and flexible, and is normally folded
up for transport in a small carry-case. Gels
Materials which are placed in front of a light
source to alter it's characteristics, e.g. color
temperature or dispersion Spectrometer A
professional-level instrument which measures the
spectrum of light. Technically speaking, a
spectrometer analyses the electromagnetic
spectrum and measures the intensity of radiation
as a function of wavelength.  Stands
Clamps Systems used to support lights and hold
them in the correct position.
13
Types of Lighting Blonde 1000-2000w, used as a
key flood light for large areas. Redhead 650-1000
w, used as a key flood light for large
areas. Pepper Light 100-1000w, small light used
as a more focused key or fill light. HMI A
high-quality type of light which uses an arc lamp
instead of filament bulb. Halogen Work
Lamp 150-500w, used as a key flood light for
lighting large areas. This is a low-budget
lighting solution. Other Lights Domestic light
bulbs can be used at a pinch, ideally as a
secondary light such as fill or
backlight. Chinese Lanterns A low-cost light,
useful in some situations. Instruments / Housing
Fresnel A light which has a lens with raised
circular ridges on its outer surface which are
used to focus the light beam.
Write a Comment
User Comments (0)
About PowerShow.com