4. The Camera's Imaging Device
The chip's target area (the
small rectangular area
near the center of this
photo) contains from
hundreds of thousands to
millions of pixel (picture
element) points, each of
which can electrically
respond to the amount of
light focused on its
surface.
5. Lens Focal Length
the distance from the optical
center of the lens to the focal
plane (target or "chip") of the
video camera when the lens is
focused at infinity
Focal length is generally
measured in millimeters
6. Angle of view
Is directly associated with lens
focal length. The longer the
focal length (in millimeters),
the narrower the angle of view
(in degrees).
You can see this relationship
by studying the drawing on the
right, which shows angles of
view for different prime
lenses.
A zoom lens operating at
maximum focal length) has a
narrow angle of view.
we would consider the angles
at the top of the drawing from
about 5 to 10 degrees in the
telephoto range.
The bottom of the drawing
(from about 45 to 90 degrees)
represents the wide-angle
range for this lens.
7. shot designations
An LS (long shot) or FS (full shot) is a
shot from the top of the head to the
feet.
An MS (medium shot) is normally a
shot from the waist up. (To save space,
we've used a vertical rather than a
horizontal format in this illustration.)
An MCU (medium close-up) is a shot
cropped between the shoulders and
the belt line, rather than at the waist.
A relatively straight-on CU (close-up)
is the most desirable for interviews.
Changing facial expressions, which are
important to understanding a
conversation, can easily be seen.
XCUs are extreme close-ups. This type
of shot is reserved for dramatic impact.
The XCU may show just the eyes of an
individual. With objects, an XCU is
often necessary to reveal important
detail.
8. F-Stops and Creative
Focus Techniques
The human eye has a focal length of
about 25mm (approximately one
inch) and covers a horizontal area of
about 25 degrees. Since we're used
to seeing the world in this
perspective, this 25-degree angle
represents a "normal" perspective for
film and TV cameras
The "f" stands for factor. An f-stop is
the ratio between the lens opening
and the lens focal length. More
specifically, the f-stop equals the
focal length divided by the size of
the lens opening
f-stop = focal length / lens opening
9. The speed of a lens is equal to its maximum (wide-open)
f-stop. Here, f / l.4 is the speed of the lens
when you open
up one stop, you
double the light
going through
the lens; when
you stop down
one stop, you cut
the amount of
light going
through the lens
in half.
10. Auto-focus Lenses
Most auto-focus devices
assume that the area
you want in sharp focus
is in the center of the
picture
in the photo right below
that the center area is
correctly focused
(thanks to auto-focus),
but the main subject is
blurry. Of course, the
goal was the opposite.
11. Focus can be switched to manual control any time by moving the focus
slider from AUTO to MAN. The user can re-engage auto focus at any
time by pressing push auto button
.
12. Minimum Light Levels for Cameras
A foot-candle, is a measure of light intensity from
a candle at a distance of one foot (under very
specific conditions). The origin of the term "lux" is
not known, although it's assumed to refer to
lumens (a measure of light power) times ten.
foot-candle is equal to about 10 lux. (Actually it's
10.76, but 10 is generally close enough,
Most professional video cameras require a light
level of at least 75 foot-candles (750 lux) to
produce the best quality video. However,
some will produce marginally acceptable
video under a few lux of light.
13. Depth of Field
The range of distance in
front of the camera that's in
sharp focus.
The larger the f-stop number
The depth of field of a lens
we set at f/11 is greater than
the same lens set at f/5.6,
and depth of field at f/5.6
will be greater than at f/2.8.
14. White Balancing On a White Card
Automatic white balance is good but is confused when faced with multiple color
temperatures. As always, the user should manually white balance
With the camera zoomed
in full frame on a pure
white card, the operator
pushes a white balance
button and the camera's
chroma channels will
automatically adjust to
produce pure white. The
camera in effect says,
"Okay,
15. Shutter Speeds and Resulting Exposure
These f-stop and
shutter speed
numbers may
seem confusing at
first, but once you
get them in mind,
they will serve
you well in video
16. Checking Viewfinder Accuracy
A tally light indicating that the camera is
recording or "on the air"
A low battery warning minutes of tape
remaining
Color balancing may be needed
low light; insufficient exposure
low-light boost (gain selector switch)
circuit in operation
Indoor/outdoor filter in place
Zoom lens setting indicating how much
further you can zoom in or out
Auto/manual iris status
f-stop setting
Shutter speed setting
Audio level meter
Remaining tape (or recording medium)
time
A zebra pattern for setting maximum
video levels
superimposed masks for the safe area
and the 4:3 and 16:9 aspect ratios
17. Camera Mounts
Using a camera tripod can make the
difference between professional
looking video and video that
screams "amateur at work.“
On most tripods the pan and tilt
head (which attaches the camera to
the tripod) is not meant to be used
for smooth panning and tilting while
shooting -- only to reposition and
lock the camera into position
between takes.
18. fluid head
It provides an adjustable resistance to pans and tilts
Exceptions to using a tripod
are in news and sports where
you must be mobile enough to
follow moving subjects,
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