Practical cinematography

Camera basicsEssentials and Aesthetics of shooting

video

Shooting formatsDV HDV

Standard definition format Hi definition (mid level)

Non widescreen (4:3) and anamorphic (16:9)

Widescreen format

Pixel dimensions 720 * 576 Pixel dimensions 1440 * 1080

Uses DV compression Uses MPEG compression

Sony VX Sony HVR

DV only HDV or DV shooting modes

MiniDV tape MiniDV tape

Essentials and Aesthetics

• Essentials– White balance, timecode, steady camera, exposure, variety and

continuity of shot sequence– A base level that you must achieve before considering the more

creative aesthetic elements– Significant marks are commonly lost on these simple things

• Aesthetics– Composition, depth, lens angles, focus effects, movement and

creative perspective– Skills that separate great shooting from adequate shooting

Subject & Object

• Object: anything in the scene

• Subject: The principle thing within the scene, the actor / presenter / interviewer / interviewee etc.

Timecode

• The units of time embedded onto recorded video for identifying segments and editing footage

• Timecode doesn’t exist on tape prior to use, it is printed on the tape when recording begins

• Timecode errors can affect you edit in negative ways– Timecode brakes and duplicate timecode

• Solution 1 – avoid constantly playing back footage as you shoot• Solution 2 – Ensure that you are always within timecode• Solution 3 – ‘black out’ your tape prior to shooting

– Insufficient pre-roll (unused tape at the start of the reel)• Solution 1 - Print bars at the beginning of the tape• Solution 2 – Set the timecode to begin at 09:59:00:00

White balanceColour temperature: •Different light sources (and sunsequently environments) emit different coloured light

– Daylight (sunrise, overcast, direct afternoon sun, sunset)– Artificial light (tungsten (typical domestic lightbulb), neon, LED)

•A camera needs to be told which kind of source it it recording•A camera set to record tungsten will record daylight as blue•The camera will need to be balanced in the environmentWhite balancing: •A white or grey card is used to reflect the ambient light in the environment - The camera is ‘told’ that this is neutral •The camera then calibrates all other colours in the scene relative to that reference point

Exposure - control

• Exposure:– The amount of light that the CCD chip is exposed to– The lightness / darkness of an image

• Cameras control exposure through:– Neutral density (ND) filters: Inbuilt neutral grey gels that absorb parts

of the incoming light– Iris diameter (aperture) – The width of the aperture (opening)

through which light passes onto the CCD chip.– Shutter speed – the shutter opens and closes letting light in while it is

open. It is measured as fractions of a second. The higher numbers indicate shorter durations for the light to pass through.

– Gain: Amplifies the values read on the CCD chip when exposed to light

Iris or shutterspeed?

• Both control the amount of light but each will have a particular effect on the image other than exposure

• Iris (aperture) – size of the opening at the lens– The wider the iris the more light AND less of the scene is in

focus (shallow depth of field)

• Shutter speed – The slower the shutter speed the more time is allowed for

light to pass through. When your shutter speed is at less than 25 (1/25 of a second = your frame rate) you will get blurred images and also strobing.

Exposure - measuring

Zebra lines•Diagonal lines overlaid onto the viewing monitor•The lines are not recorded to tape (guides only)•Zebra lines indicate two exposure values

– 100% white: used to ensure proper overall tonal range• Indicates that you are exposing part of the scene at a dangerous

level of white • You may be left with ‘burnt – out’ areas in your shot

– 75% white:• Indicates areas within the shot at 75% white• Common use is to ensure a presenters skin (usually approx. 75%

white)

Approx. 70% white (will zebra at 70 setting)

Detail at brighter parts of cloud is pushed Over 100% white (burnt out – will zebra at 100setting (right))

ZEBRA LINES – used to guage the whitevalues within your shot (tonal range)

Narrow angle of view

Narrow angle of viewSubject is magnified (zoomed in)

Wide angle of viewSubject is smaller element of wider scene (zoomed in)

Wide angle of view

This is why ‘longer’ lenses are used for greater magnification (telephoto) and ‘wider’ lenses are used for more panoramic shots

Lens angles• Wide angle of view:

– Zooming out: variable lens (long shot)– Depth is exploded – objects in background

seem further away– Depth of field is extended (deep focus)– Perspective is exaggerated and distorted

• Narrow angle of view: – Zooming in: (close up)– Depth is compressed – objects in

background seem closer– Depth of field is shortened (shallow focus)– Perspective is flattened– camera shake is magnified

Depth of field

• Large DOF (deep focus): • A large range of distances from the

camera contain objects that are in focus. – Obtained by the following:

• Narrow aperture (iris) compensated by slower shutter speed• Wide lens angle (zooming out)

• Small DOF (shallow focus): • A smaller range of distances in focus

• Large aperture (iris)• Narrow lens angle (zooming in)

Narrow angleWide Iris (aperture)

Wide angleNarrow iris

shallow focus, small depth of field (DOF

deep focus, large DOF

Depth of field

Depth of field

Focus distance

Focal length

Focal point

Depth of field

Terms related to lenses and focus

Focus

Focus• Focus distance – The distance at which the camera is

focused

• Continuous focus:– Adjusting focus within a single shot– Required where there is action– Manual continuous focus using the focus ring– Auto focus: knows where objects are but doesn’t know what

objects are important

• Fixed focus:– Isolating an object for focus (subject i.e. presenter)– Camera focus is locked at that focus distance– Objects that stray into the scene will be ignored – always focus at a narrow angle (zoomed in)

Focus issues• Issues when using shallow DOF

– Scenes with movement – subjects walking in and out of focus– Split focus: two subjects move out of focus in opposite directions.

You cannot refocus on both using a shallow DOF

• Issues when using a deep DOF– An object may appear in focus until you zoom in on it– The focus distance could be on front or behind the subject but it will appear in

focus at a wide angle

• TIP: Always zoom in on your subject to focus before framing the shot – The subject is isolated in a shallow DOF leaving less margin for error when finding the focus distance

Creative use of focus

• Pull focus– A shallow DOF is created and the focus distance is moved from one

object to another (towards the camera – ‘pull’)

• Throw focus– The same effect except that the focus distance is ‘thrown’ to an object

further away

• Moving into / out of focus– Similar to pull / throw focus except the focus distance remains static and the

objects move in and out of focus

• Defocus– Image is intentionally out of focus– Also a post production effect (graphics backdrop)

Depth cues (non 3D)• Stereoscopic (human) vision is adapted for depth perception• Cameras are inherently restricted in their ability to translate

depth (monoscopic – one eye)• Monoscopic depth cues are used to identify and enhance depth

on a 2D surface (film, TV screen etc.)– Shallow focus: isolates objects at a particular distance– Perspective (geometric): leads the eye towards a vanishing point– Scale: big = close / small = distant– Occlusion (overlap): semi obscured objects– Perspective (aerial): Objects in the distance appear faint and desaturated– Lighting: when used to pick out an area and isolate it from its foreground /

background– Motion parallax: When 2 objects move across the cameras FOV the closer

object will appear to move faster

Shallow focus

Perspective (geometric)

Scale

Lighting

Occlusion (overlap)

Perspective (aerial)