Introduction to Visual Effects

Lecture TwoPre-Production

Review of Lecture One

Basic Concepts

What’s the difference between Visual Effects and Special Effects?

• Special Effects modify the real world

• Visual Effects modify the virtual world

Special Effects modify the real world

background foreground

Action

Visual Effects modify the virtual world

Lens Sensor

Camera

Processing Image

Post-Production

Why create visual effects?• In normal photography we try to

reproduce reality

• In VFX we want to create something that doesn’t exist at all– …and also, fool people into believing

it is real

Three scenarios for VFX

• What we want to see doesn’t exist

• What we want to see is too difficult or dangerous to photograph live

• We need to “fix” something we have photographed

Format?

• Whether VFX are shot on film or video depends on what the effects will be used for

• Often effects shots require much higher resolution than the viewing format

• The ability to shoot at a variety of speeds is also a determining factor

Film Formats

• 65/70mm– When used horizontally, it’s called

IMAX

• 35mm

• 16mm (used for television)

• 8mm

Film Formats

Aspect Ratios

• Full Aperture = 1.33:1 (Silent)• Academy = 1.37:1• WideScreen = 1.85:1• VistaVision = 1.5:1 (Silent)• Cinemascope = 2.35:1• Television widescreen = 1.78:1 (16x9)

Resolution• 35mm = 4K resolution• Most VFX work is done at 2K resolution

– Why is this the case?– 4K resolution = 64MB per frame and

1.5GB/s data rate– 2K is less than half the resolution and

require less than 250MB/s data rate

Why resolution is important

• Different resolutions draw the attention of the viewer

• The process of creating an effect often degrades resolution over time

• Affects the size of your sfx plates

Different Resolutions draw our attention

• In Spiderman, it was obvious when the image switched between live action and cgi

• If the size of your image is the typical film 2K size and you need to pan across a relatively small area, your background plate will need to be substantially larger

Resolution affects the size of your sfx plate

1920 x 1080

5760 x 1450

Normal ActionFilm Speeds• 12 fps (Silent movies)

• 24 fps (all Hollywood movies)

• 25 fps (all European movies)

• 30 fps (video)

Variable speed

• High speed cameras necessary for shooting miniatures

• Camera speed at a given scale is found by the formula:

• D2 /d2= f

Lenses• Every camera has a “normal” lens

which shows objects in the same perspective as the human eye would

• A wide angle lens is shorter than a normal lens

• A telephoto or “long lens” is longer• If your normal is 25mm, then your

wide might be 12mm and your long 100mm

Wide Angle Lens• Includes a larger area than the normal lens at the

same distance– good for cramped quarters where you can’t move the camera back any farther

• Subject is smaller in the frame than with the normal lens at the same distance

• Exaggerates depth– makes elements appear farther apart than normal

• Because of the exaggerated depth movements toward or away from the camera seem faster than normal

• Because of the smaller image size, camera jiggles are less noticeable. Good for handholding the camera.

Telephoto or “Long” Lens • Includes a smaller area than the normal lens at the

same distance– good for distant subjects where you can’t move the camera closer

• Subject is larger in the frame than with the normal lens at the same distance

• Compresses depth– makes elements appear closer together than normal

• Because of the compressed distances, movements toward and away from the camera seem slower than normal

• Because of the larger image size, camera jiggles are more noticeable. Best done on the tripod.

Lens Uses• Wide angle lenses tend to distort and

spread out images, so they are useful when those types of effects are called for

• Telephoto lenses flatten out facial features and are often used for glamour photography

Wide

Normal

Telephoto

Pre-Production• Planning is the most important aspect of any

SFX production• Determine what effects are needed and why

they are needed• Determine how the effects can be achieved• Determine who will do the effects• Budget how much the effects will cost• Schedule when the effects will be done

Job Descriptions

• Visual Effects Producer

• Visual Effects Supervisor

• Art Director

• Director of Photography

• Technical Director

Visual Effects Producer

• Works with the VFX Supervisor• Responsible for budget, scheduling and

overall management of crew and facilities• Responsible for procuring crew and facilities• Responsible for delivering the project on time

and on budget• Answers to the film’s financiers and producers

Visual Effects Supervisor

• Overall responsibility for all the effects• Must provide most effective solutions to

complete required work within the given budget• Works with entire production team, including

director, DP, camera department• Designs, creates and supervises every aspect

of the film where a visual effect needs to be created

• Includes live action, model, miniature shooting as well as post-production VFX

Art Director• Also called “set designer” or “production

designer”• Analyzes the visual requirements of the script

in regard to the settings• Includes both construction and decoration of

sets• Must create visual representations through

sketches, drawings and/or miniatures• Plans, budgets and arranges creation of all

sets

Director of Photography “DP”• Responsible for capturing the director’s

creative ideas onto film or video• Must be both artist and engineer• Must understand director’s creative

vision and then accomplish it• Responsible for the overall look of the

film

Technical Director• Manages all material shot by the VFX

Supervisor• In charge of the post-production crew• Adds any CGI effects and does the

digital compositing• Manages the integration of live action

with other effects

Budgeting

• Choosing the right effects depends not only on what you are trying to convey but also what you can afford to do

• Movies are a business and effects need to be practical and cost-effective

• Use limited budgets an opportunity for creativity, not a barrier

Script Analysis

• The process of breaking down the script into elements that deal with potential effects

• Done by the VFX Supervisor

• Often shots are removed at this stage due to budget constraints

Pre-visualization

• The visual planning of your effects shots

• Pre-Viz is the battle plan for the project

• Should never be skipped

Previz on The Matrix

Pre-Viz Steps

• Collect and keep reference material

• Create and use storyboards

• Focus on the finished composition

Reference Material

• Books and Magazines• On Location• The Internet• CD Libraries (Stock footage, etc)• Keep a database of your reference

materials

Storyboards

• Shows shot composition

• Shows shot to shot continuity

• Helps you break down the shots and develop a list of requirements for each effect

Focus on the Finished Composition• Pay attention to the details

• Consider camera, focal depth, lighting, atmospheric effects

• Check your plans and your budgets