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The Great Frame Rate Debate Bruce Jacobs - Moderator Mark Schubin Larry Thorpe Doug Trumbull

The Great Frame Rate Debate Bruce Jacobs - Moderator Mark Schubin Larry Thorpe Doug Trumbull. Camera exposed 24 frames each second Fast enough for illusion of motion Shutter normally open ½ the time = 1/48 second Longer shutter = more blur, less judder Shorter shutter = less blur, more judder

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The Great Frame Rate Debate Bruce Jacobs - Moderator Mark Schubin Larry Thorpe Doug Trumbull

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  1. The Great Frame Rate DebateBruce Jacobs - ModeratorMark SchubinLarry ThorpeDoug Trumbull WGBH Public Television Quality Workshop

  2. Camera exposed 24 frames each second Fast enough for illusion of motion Shutter normally open ½ the time = 1/48 second Longer shutter = more blur, less judder Shorter shutter = less blur, more judder Projector shutter closes twice for each frame = 48 fps Avoids flicker (if projection is dim) Film Tradition WGBH Public Television Quality Workshop

  3. Camera exposed 60 fields each second (An Interlace “field” is an inferior ½ “frame”) Couldn’t “store” image and display twice, like film does Originally the rate was the power line frequency Avoided flicker on early CRTs Noticeable flicker on later large/bright/sharp CRTs No shutter needed 1/60 second exposure US Broadcasting Tradition WGBH Public Television Quality Workshop

  4. Film frames are shown 3 times, 2 times, 3 times… It’s called “3/2 pull-down” Two film frames come out even with five video “fields” US Broadcast Film Tradition WGBH Public Television Quality Workshop

  5. Digital cameras can do anything 24, 30, 60 frames per second, and more Widely varying shutter speeds available Our broadcast distribution is constrained to 60 Internet distribution can be anything? New TVs interpolate frames! The New World WGBH Public Television Quality Workshop

  6. Why 24 fps? Why not? What do I need to know to make it work? Why not 30 fps, and avoid pull-down? Should I consider other frame rates? What about 3D? When should I use unusual shutter speeds? Production Decisions WGBH Public Television Quality Workshop

  7. The “Film Look”Issues Related to Shooting atLower Picture Capture RatesLarry Thorpe WGBH Public Television Quality Workshop

  8. HD Image Acquisition • Sought-for Creative “Look” encompasses: • Lighting • Focal Length • ND Filtering • Depth of Field • Aperture • Frame Rate • Shutter • Resolution • DSP Processing

  9. 24 Hz Image Capture is a Historical Aberration…..But, • 24-frame motion picture film was born exclusively in the context of movie sound • This frame rate was perpetuated by the escalating constraint of motion picture film cost escalations with increased frame rate • Failure of SMPTE 1988 agenda for 30-Frame film standard • Over many decades cinematographers honed the art and science of motion picture capture within the constraints of this severe temporal sub-sampling • A much-loved “Look” emerged and is globally entrenched

  10. Motion Judder is More Visible • The faster the image motion • The sharper the image in motion • The brighter the Scene content • The brighter the viewing screen

  11. Cinematographer “Handles” to Manage Judder IMAGE FORMAT SIZE ND Filter CCD CMOS Imager Optical Low-Pass Pre-Filter Sample & Hold Amplifier A/D Beam Splitter Lens Post Filter A/D Imager Drive Circuits IR A/D ND Filter Frame Rate Aperture Shutter Motion of the Camera (Pan, Tilt, and Dolly)

  12. Art of the DoP: Meticulous Control of Camera Movements

  13. Art of the DoP: Shoot with Short Depth of Field

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