Camera Film and HDContinued
Basics (review) • Like an imperfect eye• Lens gathers light reflected off surfaces• A surface senses the pattern formed by differences in
brightness and color• In the case of the eye patterns of light are interpreted by the
eye
Lens and Camera• Both images are upside down• Because the eye and lenses are
convex (curve outward)• Always invert images• In the brain (or in the camera
viewfinder, the images are turned right side up)
• Work the same as still cameras • Record multiple frames per
second
HD cameras
Exposure • The amount of light that comes through the lens• The hole in the lens is called the aperture• Large apertures let in lots of light• Small apertures let in less light• An f/stop is a measure of how big or little the aperture is• Aperture numbers are fractions• F/2 means the aperture is ½ as big across as the lens is long• F/16 means that the aperture is 1/16 as big across as the lens
is long
F-stops• Each stop down admits ½
as much light as one before
• F/4 admits half as much light as F/2.8
Black and White vs Color
• BW Light sensitive emulsion and plastic base• Color Plastic base with 3 emulsion layers: Red, Green and Blue
Film Stocks • Faster Film (higher number—200 as ex. Can shoot in lower
light) • Slower Film (lower number—needs more light)
Color Temperature• Light comes in different colors
ISO• abbreviation• International Organization for Standardization.• Formerly ASA (American Standards Organization)
CCD Chips• Can only handle one color of light
source at a time• Color temperature color filters• Color temperature is a way to identify
different colors of light sources• Measured in degrees Kelvin• Lord Kelvin devised the system• Like 2500k• Coal: 2000k is the reddish light
produced at 2000 degrees Kelvin and 8000k is the bluish light produced by 8000 degrees Kelvin
• Color filters are used to convert the existing light to the color temperature required
HD Cameras • Built in filters• Set according to the
light you’ll be shooting under
• Tungsten 3200k• Mixed (Fluorescent)
4300k• Daylight 5400k• Shade 6000k
Tungsten vs Daylight • White light is made up of three primary colors• Eyes adjust • Every light has a color temperature• (Kelvin discovered that heating a block of carbon changed its
color) • His system does not relate directly to actual temperature• Lower temps are warmer and Higher temps are bluer
Daylight vs Tungsten Balanced Film
LightIs made up of three different colors
RGBA tungsten bulb and sunlight both look white to our eyes
Film and video chips are more sensitive to different light sources
Every light source has a temperature measured in degrees Kelvin
Different types of color film
500T Film “Tungsten Film”50D Film “Daylight Film”
85 orange (Filter)80a Blue (Filter)
Filters absorb light at different rates and this is called the filter factor
White Balance