1. Q G WGBH Public Television Quality Workshop 1 The Great Frame Rate Debate Bruce Jacobs - Moderator Mark Schubin Larry Thorpe Doug Trumbull

2. Q G 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)

3. Q G 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

4. Q G 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”

5. Q G 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!

6. Q G 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?

7. Q G WGBH Public Television Quality Workshop 7 The “Film Look” Issues Related to Shooting at Lower Picture Capture Rates Larry Thorpe

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

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

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