Combating flicker when recording a projector screen with a camera like a Canon, which doesn't have a sync input, involves understanding the synchronization issues between the projector's display rate and the camera's recording rate. Here's a distilled guide on how to minimize flickering and ensure smoother video quality under these circumstances:
Understanding the Issue
Frame Rate Mismatch: Flickering occurs due to the lack of synchronization between the projector's frame rate and the camera's recording frame rate. This misalignment can result in partial image captures and visible bands or flickers in the recorded video.
Start-Point Synchronization: Another challenge is aligning the start point of image drawing between the projector and the camera, which is largely left to chance without a common sync feature.
Practical Solutions
1. Match Frame Rates
Adjust Camera Settings: Ensure the camera and projector operate at compatible frame rates. This might require checking the projector's settings or manual to match the camera's frame rate accordingly.
Geographical Considerations: Use 60i or 30p FPS in America and Japan, or 50i or 25p in Europe, aligning with the local electrical system frequency to reduce flicker.
2. Optimize Camera Settings
Lower Shutter Time: Slowing down the shutter speed can help minimize flicker. However, this makes the footage more susceptible to motion blur.
Increase F-Stop: Using a higher f-stop value or adding a Neutral Density (ND) filter can also reduce flicker by decreasing the amount of light entering the lens.
Progressive Recording Mode: Experiment with progressive (e.g., 30p or 25p) rather than interlaced recording modes to see if flicker decreases.
3. Post-Production Workarounds
Acquire Presentation Files: If possible, request a copy of the presentation materials to extract stills or video clips. These can be edited into your footage in post-production, offering a flicker-free alternative to directly recording the screen.
Camera Positioning: Focus on capturing the presenter with your camera rather than the projected screen. Note the presentation's progression to match the corresponding slides or videos in your final edit accurately.
Additional Tips
Test and Adjust: Conduct tests before the actual recording to find the optimal settings combination for your specific situation.
Be Prepared: Having access to the presentation files beforehand allows for better planning and can significantly enhance the final video's quality by providing clear, flicker-free visuals to supplement the recorded content.
Adopting these strategies can greatly improve the quality of videos involving projector screens, mitigating the common issue of flicker and ensuring a more professional outcome.