4 Functions Controlled By Lens
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Transcript of 4 Functions Controlled By Lens
4 Functions Controlled By Lens Image focus- 3 techniques?
1. Turn a ring on barrel of lens
2. Zoom in, set focus, zoom out
3. Tape measure: measure camera to subject distance, set ring accordingly
4 Functions Controlled By LensQuantity of light- How do you determine f-stops?
focal length ------------------ = f-stops
lens diameter
-focal length- distance from focal plane (film) to optical centre of the lens)
*Remember: Lower # = Bigger Aperture
Quantity of Light Fast Lenses=?
-Larger maximum aperture-This leads to…
-shorter (faster) exposure time-capable of very shallow DOF
Slow Lenses=?-Smaller maximum aperture-This leads to…
-longer (slower) exposure time-NOT capable of very shallow DOF
4 Functions Controlled By Lens Image Area-
Each focal length has a given angle of view:
Short/Wide-21mm-35mm; curved/distorted
“Normal”- 50mm; approximates human sight
Narrow/Long-105mm-300mm; a.k.a. “telephoto,” creates a ‘flat’ image
4 Functions Controlled By Lens Depth of Field-
-Zone of focus between closest and farthest parts of the picture that are reasonably sharp.
-Controlled by three factors:– Lens Opening (Size of Aperture)
-smaller aperture=greater DOF-thus, high f-stop=greater DOF
– Focus Distance (camera to subject distance)-farther distance=greater DOF
– Focal Length (lens to focal plane)-shorter focal length=greater DOF
*Remember: Depth of Field extends about twice as far behind the plane at which the lens is focused as in front.
Depth of FieldWhat is hyperfocal distance?
-When camera is focused at this distance, DOF extends from ½ hyperfocal distance to infinity (∞).
Depth of Focus ≠ Depth of Field
Depth of Focus IS…
-Tolerance in the accuracy of the seating of the lens-The distance on either side of the focal plane where the film or CCD can be seated and still record an acceptably sharp image
The Lens and PerceptionDefine “Size Constancy”
-A perceptual distortion that causes a mismatch between how we see an image and how a lens records it (I.e., optical illusions-created in the mind, not the eye/lens)
Why is this important?-May lead to discrepancies between how we perceive something and how the lens actually records it on film.
Shutter Speed, Aperture and Film Speed Shutter Speed is measured by…
- Fractions of a second.- 4 = ¼, 8 = ⅛, etc., so bigger #’s = SHORTER amount of
time.
The size of the Aperture is measured in…- The size of the aperture is measured in F-STOPS.- The larger the f-stop #, the smaller the aperture.- F-stop = focal length/lens diameter
Common (ASA) film speeds include 50, 100, 200 ,400, etc. What does this doubling mean?-The doubling indicates that the film needs half as much
exposure time, or is TWICE as fast.
Shutter Speed, Aperture and Film Speed (summary):
Shutter speed: Each # increase denotes…
- A halving of the time the shutter is open
Aperture: Each f-stop increase denotes…
- A halving of the diameter of the aperture
Film speed: Each increase in ASA denotes…
-A halving of required exposure time for a given subject
Visual Design:Name the SEVEN VISUAL ELEMENTS:
1.) Space
2.) Line
3.) Shape
4.) Tone
5.) Colour
6.) Movement
7.) Rhythm
Visual Design: SpaceOpen Vs. Closed Space:
-Closed space…
…leaves NO room for interpretation: all the information you need is included in the frame.
-Open Space…
…DOES leave room for interpretation; for example, when a character is facing/reaching off screen, we don’t know what they’re reaching for.
Visual Design: LineName the EMOTIONAL QUALITIES of each type.
Horizontal
-Associated with stability, balance, restfulness/serenity.
Vertical
-Associated with power, strength.Diagonal
-Associated with confusion, chaos, internal struggles, tension, instability/imbalance.
Visual Design: Tone Define TONE.
- The value (light/dark) of objects in the shot.
- I.e., contrast vs. affinity.
What are the THREE ways to control TONE? 1. Art Direction (reflective)
2. Lighting (incident)
3. Exposure (less selective)
What is coincidence/non-coincidence?-Value range reveals the subject of the shot.
-Value range (partially) obscures the subject.
Visual Design: ColourWhat are the THREE attributes of COLOUR?
1.) Hue-
-red, orange, yellow, green, cyan, blue, violet
2.) Brightness--value/tonal range of colours, achieved by adding
black or white
3.) Saturation--saturation is the purity of the hue (more or less
grey)
-yellow desaturates to the lightest grey, while violet desaturates to the darkest grey.
Visual Design: MovementName the 2-DIMENSIONAL camera
movements.-pan, tilt, zoom
Name the 3-DIMENSIONAL camera movements.-dolly/track, boom, crane
*Define continuum of movement within the shot.
Visual Design: RhythmHow is visual rhythm created?
-Strategic use of stationary/moving objects and editing.
Define Alternation.-change
Define Repetition (of an alternation).Define Tempo (of the repetition of the
alternation).
Graphing Visual StructureContrast vs. AffinityWhat do a progression, a constant and
contrast/affinity look like as graphs?
-Progression=SLOPING line
-Constant=STRAIGHT line
-Contrast/Affinity=sudden SPIKE
Visual Structure Remember the Rule of Thirds Define “Headroom”
-Compositional space (negative space) above subject’s head. Define “Eye-room”
-Compositional space given in the direction the subject is looking (horror movie vs. other)
What are the common ASPECT RATIOS?-TV (standard def.): 4:3-HDTV: 16:9-Movie Theatre: 1:85:1; 2:39:1
The Shot: Hybrids/Hollywood Slang ECU
MCU/”Two T’s”
“Cowboy”
“Head to toe”
Tight shots/close shots
Wide/Master/Est. shots
Extreme close-up (less than whole face)
From mid-chest up From just above the
knee (MLS)- shows belt buckle
Full-body shot/full shot
A.k.a. Close-Up (CU)
A.k.a. Long Shot (LS)
The Shot: AnglesDefine High Angle.
-Camera placed ABOVE subject.
Define Low Angle.
-Camera placed BELOW subject.
Define Canted.
-Camera tilted laterally.
The Shot: Coverage Define Master Shot (MS/LS/Est.) Define Over the Shoulder (OS) Define “Cutaways”
-a shot to which the editor can cut in order to show an action or solve an editing problem.
Reaction shots Inserts
-Similar to Reaction shots; an insert is a shot of part of a scene as filmed from a different angle and/or focal length from the master shot. Inserts cover action already covered in the master shot, but emphasize a different aspect of that action due to the different framing. An insert is different from a cutaway in that the cutaway is of action not covered in the master shot.
Screen Grammar: What is Rabiger’s Approach?
Film works across cultures because it emulates human thought/the way our minds work.
Screen Grammar:According to Rabiger, what parallels are there in nature for…
Brief Shots
Held Shots
Close Shots
Wide Shots
Cursory glances used to orient ourselves
Long looks in which we indulge
Reproduce sensation of taking a detailed, focused look at something
Emulates the way we look at things that are large, busy or distant
Screen Grammar: Rabiger According to Rabiger, what motivates a moving-
camera shot in real life? -subject motivated (following target/moving object)
-search motivated (looking for a person/object)
-boredom motivated: reproduces natural tendency for wandering eye/attention
What are the THREE phases of a Moving-Camera Shot?1. Starting Composition
2. Movement
3. Ending Composition
Screen Grammar: Master Scene Technique
What is the “classic pattern” ?
MS > LS > Singles/OS > CU > Cutaways/Inserts
Define “Master Scene Technique”Approach in which director stages/shoots scene pretty much as it would be done in a theatre; all or part of scene is filmed in MS (a.k.a. est. shot), in which all/most of it’s elements are presented together.
What are some practical issues that arise?-How best to film CU’s; shooting out of sequence; who to cover first; off-camera dialogue
Screen Grammar: Shot/Reverse-Shot Technique
Define Shot/Reverse-Shot Technique.
-Involves 2 camera set-ups: 1 for person A, 1 for person B. Cut together creates a simple, back-and-forth exchange (good for conversations).
180 Degree Rule (the “line”/”axis”)
Can a scene have multiple/changing lines?-Yes, if there are multiple characters or moving
characters.
The Rule requires constant awareness of the actors’ ____?____
-eye-lines (lines of sight- to left or right?) Crossing the line intentionally is called a…
-Jump Cut Multiple characters = multiple…
-”lines”
Screen DirectionMaintain screen direction on entrances
and exits when scenes are close together _________ and __________.
-Geographically and temporally.
What two types of movement can change screen direction within a shot?
-Camera movement
-Object movement
Directorial Communication Tools:Name all FOUR.
1.) Shotlists
2.) Overheads
3.) Lined Script
4.) Storyboards
ScreenwritingKnow formatting.What is the fatal flaw of screenwriting?
-Passivity.What kind of descriptions should/should not
be included?-Script should include only what can be seen/heard; AVOID describing inner thoughts/emotions.
What is the Vonnegut Formula for a story?- ? ! .
Script Analysis According to Weston, what is the FIRST step?
-Cross out all screen directions- those are the director’s job!
Next?-Read the script allowed and compile first impressions.
What are “The Immutables” ?-Facts and Images which are implicitly stated and thus not subject to interpretation.
Next?-Imaginative choices- interpretation, including motivation (what’s at stake?) and choosing specific objectives and actions for each scene and each _______ within the scene.
A story can be divided up into major ______. Likewise, a scene can be divided into smaller _______.-events; beats.
Film/Video InterfaceDefine the two perceptual phenomena
that may explain perception of motion.
1.) Persistence of Vision:-an optical/perceptual phenomenon that prevents us
from seeing the dark space between the film frames by causing “flicker fusion”
2.) Phi Phenomenon:-also known at the “stroboscopic effect.” Creates
apparent movement from frame to frame.
Exposure time and Shutter Angle Formula
Exp. Time (Shttr Speed) = (1/Speed in FPS) X (angl of Shttr Opening/360)
(MEMORIZE)
Overcranking/UndercrankingDefine overcranking.
-To shoot at more than 48 frames per second (doing 72 slows it WAY down) - makes SLOW motion when played at 24 fps
Define undercranking.-To shoot at 12 fps - makes FAST motion when
played at 24 fps
Calculating Film LengthsHow many feet per minute for 35mm?
90ft / minute
How many feet per minute for 16mm?
36ft / minute
What are the layers in a piece of film?
1. Blue Sensitive Emulsion }
2. Yellow Dye } ***3. Green Sensitive Emulsion } In black & white
4. Magenta Dye } white film, only
5. Red-Sensitive Emulsion } ONE emulsion
6. Cyan Dye } layer.
7. Antihalation Layer
8. Base
Colour Temperature When shooting
Tungsten(indoor) balanced film outdoors, use…
This filter cuts ____ stops of light.
When shooting daylight balanced film in a Tungsten(indoor) situation, use…
This filter cuts ____ stops of light.
An amber filter (an 85)
2/3 of a stop
A blue filter (an 80a)
2 & 2/3 stops
Keeping Track of FilmWhat is the difference between
EDGE NUMBERS/KEY NUMBERS and KEYCODE?
-Edge/Key NUMBERS= #’s photographically printed between sprockets on raw film stocks.
-KeyCODE= (a sort of barCODE); electronically readable version of edge numbers, used during telecineing.
Video Controls
• Exposure (f stops)• Exposure Index (light sensitivity)• Depth of field• Colour balance (white balance)
Video Standards: NTSC
PAL/SECAM
HDTV
U.S. standard for TV: 2 interlaced frames, 29.97(~30)fps, 525 lines
European standard: 25fps (50 fields), 625 interlaced lines
720 or 1080i –only 1080 is interlaced, progressive (lines placed sequentially)
Define compression.Discarding of redundant digital
information/data in order to facilitate more efficient storage/recall of video footage (employed heavily with mini-DV format).
Colour Space
Refers to sampling rates for luminance and colour.
Luminance:Red:Blue
4 : 1 : 1 = DV
^Higher # = better.
Drop Frame Time-code = ? Drop frame timecode: drops average of 1.8
frame numbers (not frames!) per minute to account for fact that video is running at 29.97, not 30 frames per second.
Drops the ;00 and ;01 every minute except for the tenth minute.
Non-drop-frame timecode does not drop those frame numbers
Maintaining Continuity:According to lecture, what is the MOST
IMPORTANT part of continuity shooting?
-Overlapping action!
Lighting Eye light
Set light
Kicker
Accent Light
Practicals
often mounted near or on the camera. Puts a sparkle in the actor's eye
Illuminates the furniture and walls
similar to backlight, though traditionally lower and on the opposite side of the key
glint of a knife, glow of a wine bottle
light sources that are part of the scene
High Key/Low Key Lighting
HIGH KEY: Bright, flat
Little contrast of tone
Comedies, musicals, sitcoms
LOW KEY: Dark, Moody,
Atmospheric Significant contrast
of tone Horror, film noir,
mysteries, crime stories
Quality of Light: Specular vs. Diffused
SPECULAR: direct, hard light that
creates harsh shadows. Best example is the SUN
DIFFUSED: indirect, softer light
that creates diffused shadows. Diffused light passes through a medium (e.g. clouds) or diffusing material is reflected
Kelvin Scale & Colour Temp. 1500K 2800K 3200K
5500K
7-9000K
Candle Light 60-watt Bulb Tungsten Light/Film
Studio Lights Noon Summer
Sunlight Sunlight when
cloudy
Using Incident Light Meters measures foot-candles and suggests a f-stop for normal
exposure
Foot-candles = ?
-amount of light that falls one foot in any direction from a candle
Latitude (define it).Latitude is the "seeing range" of the
film, the amount of under or overexposure that the film stock can accept and still render objects with detail
Choosing An F-StopWhat to consider?
-Existing light/quality of light
-Depth of field: lower f-stop means shallower depth of field BUT sharper resolution
-Decide which areas you want to be middle grey/exposed (not under or over) and expose for
those.
Electricity BasicsWhat is the equation for calculating how
many watts of equipment you can hook up to a circuit?
Watts ÷ Volts = Amps
*Remember: US standard= 120 Volts
Electricity Basics in PracticeHow many amps per every 120 watts?
120watts ÷ 120volts= 1 Amp
What is a good safety margin for this?
1 Amp per every 100watts.
The Inverse Square Rule is…The intensity of light decreases by the
SQUARE of the distance away from the subject.
So if a light is moved from 10ft to 20ft away, how much is its intensity decreased?
10X10=100 20X20= 400 So, about FOUR times
Editing with Walter MurchAccording to Murch, the ideal cut would
meet all 6 of these criteria (in order):
1. Emotion
2. Story
3. Rhythm
4. Eye-Trace
5. 2-Dimensional Plane of Screen
6. 3-Dimensional Plane of Screen
Classic Hollywood Editing In this style, the story unfolds in ___________ order.
Within the scene, editing creates the illusion of ________ ______ and ________.
Classic Hollywood editing uses the _______ ________ technique.
chronological
Continuous time space
Master Scene
Why Cuts WorkName the two possible reasons why our
brains can accept cuts in movies.
1.) Cuts approximate the times of images we see in our dreams.
2.) Cuts resemble blinks, which serve to visually separate the two ideas in order to better juxtapose them mentally.
The crowbars of directing are…
What are you trying to MAKE the actor do?
What are you trying to GET the actor to do?
These questions involve 3 things:
1. A verb
2. A receiver
3. A desired response
What is one of the most important things to determine in casting?
Does the actor listen to the other actors AND the director?
4 Criteria to consider in casting:
Actor's ability (intuitive equipment,acting skills, physical abilities, artistic sensibility, heart)
Whether the actor is right for the part (does NOT mean physically)
Directibility
Casting relationships (cast the ensemble, not just the individual roles)
What are the stages of an audition?
• Check in• Greeting• Chit chat• The reading• Adjustment• Judge• Thanks and praise• Call backs
Above vs. Below the line Money negotiated/spent
BEFORE filming.
Rights to material on which the screenplay is based, the salaries for the screenwriter, director, producer, and actors.
In contrast to Above-the-Line, BELOW-the-line budget is usually FIXED.
Salaries of the non-starring cast members and the technical crew, as well as use of the film studio and its technical equipment, travel, location, and catering costs, etc.
What are the properties of physical sound? (5)
1. Propagation (process by which sound is transmitted through a medium as vibration)
2. Medium (substance through which sound travels)
3. Speed (1130 ft/second in air at room temperature, much slower than the speed of light)
4. Amplitude (vertical dimension of the wave, measured in dB -> loudness)
5. Wavelength and Frequency (number of occurrences of a wave per second, measured in Hz -> pitch)
Amplitude: Doubling of perceived loudness occurs at…
An increase of approximately 10 dB
The threshold of pain starts at…
…around 120 dB
How does the INVERSE SQUARE RULE apply to SOUND?
When the distance to a sound source DOUBLES, the size of the disturbance (level) diminishes to ONE QUARTER of
its original size.
Are short waves or long waves more easily absorbed by the atmosphere?
SHORT.
Why do sounds heard from far away seem low/”bassy” ?
All the higher frequencies have been absorbed by the time the sound reaches your ear.
Reflection (of sound)Much like light bouncing off a flat mirror,
when sound bounces of a hard, flat (non-absorbent) surface, the angle of ________ equals the angle of ________.incidence reflection
What is the effect of the Doppler Shift?
Sound generators in motion produce a perceived higher frequency as they approach a point of observation, and a corresponding lowering of the frequency as the object recedes.
Think of cars going by on a race track.
Room Acoustics: Name the THREE Sound Fields.
1.Direct Sound
2.Discrete Reflections
3.Reverberant Field
What are the TWO FACTORS that affect reverberation time?
Volume of the room.
Absorption of the surface area of the room.
Hearing Conservation
Hearing loss begins to occur when sound level is above ______. This is called the _______ _______.
Every _______ louder cuts the safely allowed time by _______.
80 dBthreshold level
3 dBhalf
What is the Loudness Effect?Known as the “______ ___" of hearing. It takes a finite amount of time for
loudness to grow to its full value. The range time for a high level but brief sound to reach nearly its full loudness is between 35 and 300 ms (__to __ frames at 24 fps).
integration time
1 8
Spatial Perception (of sound) The _________ Effect describes how we locate
sound using the first-arriving wavefront.
INFLUENCE OF SIGHT: For professionals, just a ___ degree mismatch on a horizontal plane between the visual and aural positioning is noticeable, whereas for the average layperson it takes ___ degrees.
THE COCKTAIL PARTY EFFECT: Also known as ______ __________ : the ability to discriminate sounds better through the use of 2 ears than through recording.
Precedence
4
15
Binaural Discrimination
Auditory Streams…Murch says that hearing can only attend
to __ of __ sounds presented at a time, so no more than __ foreground audio streams should occur simultaneously.
1 3
3
Speech Perception Is it better to “pan” dialogue to wherever
the person speaking is located or to keep it centred no matter what?
-keep it centred!
Name one instance when “panning” might be used for dialogue.
-for dialogue coming from characters off screen.
Frequency Response is…How evenly or completely a recorder or
playback format reproduces the audible range.
Humans can (generally) hear between ______ and _____ (Hz/kHz).
20 Hz – 20 kHz
Dynamic Range of audio equipment:
Dynamic Range is stated in _______ (unit) and is defined as _____ to _____ ratio.
The “overload level” or “headroom” refers to the threshold or level at which ______ occurs.
dB (decibels)signal noise
distortion
Is it better to process the signal while recording or in post?
In POST! It is best to get as clean a recording as possible.
Quantizing
This is the process of turning a waves Amplitude from _______ to ________ by assigning numerical values to each point on the waves, which correspond to it’s ________ at that point.
analog digital
loudness
SamplingSample rate is a little more than ______
the highest frequency in the desired bandwidth.
twice
Sound ResolutionThe number of bits being used to
represent the amplitude dimension, the number of stacked bins.
Did we use single or double system recording?
Single: Sound and image were recorded on the
same device (DV camcorder).
What is the correct order for calling a shot?
AD: Lock it up AD: Roll sound Sound Mixer rolls the recorder, verbally slates the
scene and take, “Speed” AD: Roll Camera Camera Operator, when camera is running: “Rolling” 2nd AC: “Marker”, then bangs the slate and exits Camera Operator: “Set” Director: Action Director: Cut or Tail Sticks/Tail Slate
Phase CancellationWhat is it?
-When 2 or more mics are going to the same channel, if they receive the sound at slightly different times (one at the top of the wave, one at the bottom), it can create an effect that cancels out some/all of the sound.
What Rule can prevent this?-The 3-1 Rule: No 2 mics should be close together than 3 time the distance from them to the subject.
What is the difference between a traditional Narration-Based Documentary and a Personal Essay style documentary?
Not necessarily any difference in structure:
Can still be clear narrative/message, edited for time, with narration as backbone BUT…
…a Personal Essay documentary features a personal story in which themes and messages are delivered from a SUBJECTIVE narrative perspective.