Study Guide for Final Chapter 13 Motion Film Motion What is a Film Frame 12 07 2015 o A Film Frame is the Basic Structural Unit of Film o Film frames show the object at rest regardless of whether it was in motion when it was shot snapshots of moving objects Frames Per Second FPS o Film creates the illusion of motion by taking 24 frames per seconds FPS and then playing them back at high speed o Think of a little flip book in which each page shows a drawing slightly different then the previous one and when you let the pages flip rapidly the drawings seem to be in motion o Why we see this position change as movement is based on the apparent motion or stroboscopic illusion o Every film frame shows a unique at position in the time continuum a snapshot of part of the motion Persistence of Vision o The theory that when we look at an image an afterimage persists in our retinas for about 1 25th of a second o This is why we do not see the black between frames The only real motion in film occurs when the projector pulls down frame after frame in front of the light source During this motion the screen is blacked out so we do not witness the pull down of each frame o Our perception of continuous movement when actually seeing o In combination with persistence of vision this is why we see separate objects move motion in film projection Phi Phenomenon Video Motion What is Scanning o Scanning can either be progressive or interlaced Difference between Progressive and Interlaced o Interlaced All of the odd lines of a frame are scanned at once then all of the even lines are scanned Our eyes see as one image Reduces flicker Uses less bandwidth o Progressive Each line is scanned one at a time from top to bottom Sharper Better motion o Frames of Reference Figure Ground Principle o Whenever you perceive motion you automatically establish a frame of reference by which you judge the direction of the vector and its relative speed o This frame of reference establishes a figure ground relationship We have the tendency to organize a scene into figures that lie in front of a background In doing so we perceive the ground as being more stable than the figures You normally perceive a moving object relative to its immediately more stable environment What you do in effect is establish hierarchical relationships of dependence Figure Ground Reversal o Sometimes the motion paradox can play tricks on you especially when you are confused about which object is doing the moving This figure ground reversal can occur when you sit in your car next to a large bus waiting for the stoplight to turn green When the bus inches forward trying to get a jump on you you may feel as though your car is rolling backward even though your foot is on the brake What is moving you or the car next to you o This principle is how car scenes were filmed for much of early cinema Dr No car chase scene made his car seem to be moving because of the car in the background getting closer and larger We can stimulate object motion on the screen by having the object figure remain stationary and the background move through a rear screen projection or a chroma key Because we know from experience that it is more likely for the car to move than the city street we perceive the street as the more stable ground against which the less stable figure the car is moving Perceived Speed What is perceived speed o refers to how fast or slowly we sense something moving on screen It includes Object Speed The Focal Length of the Lens how fast the object was actually traveling when recorded position Blocking moving object the camera placement in relation to the event or moving object The camera s point of view relative to the A specific zoom lens Object Speed o In an actual environment we have a built in sense of object speed what is fast or slow o When we watch movies however that built in time sense for speed no longer works We need something to tell us how fast objects are moving Screen motion is almost always manipulated that is purposely distorted through lens choice and camera point of view Lens Choice and Blocking o The perceived screen motion is greatly dependent on the focal length of the zoom lens position and where you place the camera in relation to the event Focal Length of Lens and Perceived Speed o Wide Angle Lens and Perceived Speed Motion on the x axis seems slower in wide angle The field of view is larger the space to pass is o Motion on the z axis seems faster in wide angle A wide angle lens exaggerates the perceived z axis greater speed The person object gets significantly larger as it is approaching the camera We interpret this rapid change in image size as a high magnitude motion vector the object rapidly moving toward the camera Same process occurs in reverse when she moves away from the camera wide angle lens shows it moving at a rapid pace The z axis is expanded o Telephoto Narrow Angle Lens and Perceived Speed Motion on the x axis seems faster in telephoto Field of view is smaller less space to pass Motion on the z axis seems slower in telephoto The image size of the object changes only slightly even though it is covering the same distance at the same speed We interpret this small change in image size as slow z axis speed When in a very long focal length position the zoom lens can virtually eliminate the feeling of movement along the z axis Similar aesthetic result to the slow motion effect Properties of Slow Motion o An object in slow motion does not simply move more slowly than usual it seems to move through a denser medium than air which appears to cushion the effect of gravity and make the motion woolly and soft o Can give us a close up in time effect prolonging duration o Slow motion introduces a feeling of surreality Motion vector no longer obeys the physical laws of gravity direction seems more erratic o Principal Factors that distinguish slow motion from something moving a little more slowly than normal Frame Density Absence of Gravity o Slow motion has high frame density 24 FPS to 48 FPS to 24 FPS This is the most effective slow motion effect o Most compelling aesthetic effect is that it seems to free an object from the force of gravity Object appears weightless and its direction seems unpredictable Ex When you watch a slow motion replay of a fumble during a football game the ball rolls and bounces agonizingly slowly and without much apparent sense of direction with the player just a breath away Can also imply superpowers in people or
View Full Document
Unlocking...