120 fps

Definition & Fundamentals

120 fps (120 Frames Per Second) is a high-frequency capture rate used to record motion with extreme detail. When played back on a standard 24fps or 25fps timeline, it creates slow-motion with precise 5x deceleration (120÷24=5), allowing audiences to follow fast movements in complete detail.

120 fps is deployed primarily in three contexts:

1. Dramatic slow-motion – Cinematic effects for emotional or action moments
2. Technical analysis – Detailed motion studies for choreography or effects
3. Variable Frame Rate (VFR) hybrid workflows – Quick cuts between normal and slow-motion

Technical Requirements

Camera hardware:

• Minimum requirement: 1/120 sec shutter opening (at 180° shutter angle)
• Practical shutter line: 1/240 sec (90° shutter at 120fps) or 1/180 sec
• Rolling shutter window: ~8.3ms per line (CMOS sensors only)
• Sensor read-out speed: Minimum 2000 fps effective bandwidth required

Cameras with native 120fps capability:

• Sony FX30 / FX3 (4K @ 120fps via firmware update)
• Blackmagic Pocket Cinema 4K / 6K (6K @ 50fps base, 4K @ 120fps)
• Canon EOS R5C (4K @ 120fps in DCI-4K mode)
• Panasonic Lumix S1H (4K @ 120fps firmware upgrade)
• RED Komodo (6K @ 120fps native)

Sensor-limited resolutions:

• 4K @ 120fps: Reduced sensor area (crop) on most cameras
• HD @ 120fps: Fully available on all modern cameras
• DCI 4K @ 120fps: Standard on cinema cameras (RED, Blackmagic)

Lighting Requirements

Exposure challenge:
The shutter opening at 120fps is half as long as at 60fps (or 4x shorter than standard 24fps):

Practical consequences:

• Light output doubling required: 12k HMI instead of 6k HMI for comparable exterior shots
• Larger aperture: T2.0 instead of T2.8 required (depth-of-field challenge)
• High-speed ND filters: Variable ND recommended (prevents aperture depth-of-field issues)
• Flicker-free LED panels: Essential for lighting

Lighting scenario example (Sony FX30, 4K @ 120fps, 90° shutter):

• Interior scene: ~4000 lux required (vs. ~500 lux for 24fps)
• Exterior daytime: ISO 500+ required or ND filter removed
• Golden hour sunset: Impossible with standard lenses; 35mm SLR-speed or faster required

Motion Planning & Choreography

Motion design principles at 120fps:

1. Fast movements become comprehensible – Advantage

• Explosion: Dust particles visible
• Water splash: Individual water droplets tracked
• Glass break: Fracture geometry discernible

1. Slow movements appear exaggerated – Potential pitfalls

• Actor movement: Expansive gestures required
• Camera movement: Pan speed 3-5° per second appears normal (normally 15-20°/sec)
• Fine movements (fingers, eyes): Must be "more generous"

Actor briefing:

• "Choreograph movements 50% larger/more sweeping"
• Focus puller: "+15-20% tolerance range for depth-of-field errors visible"
• Editorial: "Slow-motion sequences require 2-3x longer cutting disadvantages"

Storage & Data Requirements

Bandwidth doubling:

Storage duration for 1 hour of shooting:

• 4K ProRes 422 @ 120fps: ~900 GB SSD required
• 6K DCI @ 120fps (RED): ~1.2 TB SSD required
• HD @ 120fps (backup): ~180 GB SSD

Recommended storage hardware:

• Primary recorder: Blackmagic Video Assist Pro with Thunderbolt SSD (R7 SSD 1TB = €850)
• Backup: Two parallel SSDs for data backup during outdoor work
• Archive: After shoot day: LTO-7 tape or redundant HDD archiving

Editing & Post-Production

Timeline handling:

• Edit sequence remains standard 24fps
• 120fps material is placed on 24fps timeline at "60%" speed (yields 5x slow-motion)
• Alternatively: 48fps timeline for "more natural" slow-motion (120fps @ 40% = 2.5x deceleration)

Color grading complexity:

• Sensor noise: High ISO (400-1600) needed for 120fps → noise more visible in 5x slow-motion
• Flicker artifacts: LED panel flicker (strobe) becomes banding artifacts in slow-motion
• Motion blur artifacts: If original motion-blur too minimal (fast shutter), slow-motion looks "choppy"

DaVinci render time:

• 120fps RAW grading: ~5x longer export time than 24fps
• Cache requirement: +2.5 TB RAID storage for complex nesting operations

Practical Application Scenarios

Action sequences:

• Car crash: 120fps for impact details
• Gunfire effects: Bullet casing trajectory
• Explosion & fire: Flame geometry in complete detail
• Kick/punch/impact: Fight choreography legible

Characterization & emotion:

• Tear moment: Tear film across cheek visible
• Laughter: Tooth placement, mouth corner details reveal "genuine" smile
• Blink: Emotional blinking discernible
• Hair flow: Wind effects dramatized

Technical/specialty applications:

• High-speed processes made visible (wing beat, propeller)
• Color-science tests (how does color change with slow movements?)
• Focus-breathing analysis (lens behavior under focus pull)

Common Mistakes & Solutions

Comparison: 60fps vs. 120fps vs. 240fps

Equipment Checklist for 120fps Production

Camera & optics:

• [ ] Camera with native 120fps (FX30, R5C, RED Komodo, BM Pocket 6K)
• [ ] Lenses T2.0 or better (Zeiss Master, Cooke Anamorphic)
• [ ] Variable ND filter (Formatt Firecrest HD or Tiffen Diamond)
• [ ] Cine motorized focus servo (higher precision required)

Lighting:

• [ ] 4x 6k HMI or equivalent LED (Aputure 600Pro, Kino Flo 4Bank)
• [ ] 2x 2.5k HMI for fill light
• [ ] High-speed dimmer (flicker-free, minimum 3kHz PWM)
• [ ] ND filter set (1-4 stops) for external control

Storage & recording:

• [ ] Two 1TB Thunderbolt SSDs (for backup redundancy)
• [ ] External SSD rack (Sonnet or Akitio enclosure)
• [ ] Blackmagic Video Assist Pro 7" (for on-set monitoring)
• [ ] LTO-7 tape or redundant HDD for archiving

Grip & support:

• [ ] Stable tripod + fluid head (Sachtler FSB4, Miller Compass)
• [ ] Follow-focus servo with precision gearing
• [ ] Monitor arm with gimbal for focus visualization
• [ ] Cable management system (velcro straps, snake cables)

Post-production:

• [ ] DaVinci Resolve Studio (GPU acceleration for RAW @ 120fps)
• [ ] 3-4 TB additional RAID storage (cache/render)
• [ ] Calibrated reference monitor (for slow-motion evaluation)
• [ ] Proxy workflow automation (Resolve Fusion Lite)

Perspectives from Film Professionals

Cinematographer:
"As a cinematographer, I appreciate 120 fps for the incredible flexibility in depicting motion – every gesture becomes visual artwork. The technical challenge lies in significantly higher light requirements (approximately 8,000-12,000 lux instead of 1,500-2,000 lux at 24 fps) and precise focusing – every blur is ruthlessly visible in slow-motion. I must work with high-speed focus systems or manually follow with extreme precision. Memory cards fill quickly – one hour of 4K 120 fps requires 12-15 TB. I plan in advance exactly which moments warrant 120-fps treatment."

Director:
"As a director, 120 fps is a powerful storytelling tool to amplify emotional peaks or stage action sequences dramatically. When I slow 120 fps to 5x slow-motion, it allows me to give a moment unlimited time – the audience can absorb every nuance. I deploy this technique very selectively and sparingly, as overuse makes the entire film feel uniformly slowed and loses emotional impact. Often I combine 24 fps (emotional, intimate) with 120 fps (immediate, real) for maximum contrast."

Colorist:
"120 fps is the highest demand in grading. The crystal-clear sharpness means I must grade every single frame perfectly – no hiding behind motion blur. Color transitions require frame-by-frame verification. Sensor noise becomes more visible in 5x slow-motion, requiring more noise reduction. LED flicker artifacts become banding problems in slow-motion. The material is extremely demanding, but pays off in artistic control – every color tone is consciously chosen."

Producer:
"From a production standpoint, 120 fps means significantly higher costs: 5-8x higher lighting expenses, 5x higher storage costs, 40-50% longer post-production times (rendering, grading, VFX grow exponentially with this data volume). I budget 30-40% additional time and budget for 120-fps sequences. Add complex storage infrastructure – 12-15 TB per hour of footage requires dedicated data management systems and redundant backups (LTO tape or RAID 6). However: for high-end commercials, luxury brands, and prestige content, the visual quality and artistic control justify this investment."