Motion blur: long kernels, pan backgrounds, and rolling-shutter traps
Motion blur stretches pixels along the trajectory—background crisp while a runner smears, or panning that streaks architecture behind a sharp-ish car—distinct from global shake or uniform defocus. `motion-blur-correct` shows up on stages, fields, traffic long exposures, and kids at play. Very long blur kernels make single-frame deconvolution hallucinate in low-texture skies; electronic shutter can skew verticals, which is geometry, not a simple line kernel, so naive “de-motion” may worsen skew. Sometimes misfocus masquerades as motion when only the subject is soft—decide the dominant failure mode before cranking sliders. A slightly sharper neighbor frame in a burst is often the honest fix versus forcing one hopeless frame. After correction, inspect wheel spokes, fence pickets, and jersey lettering for breaks or duplicated ghosts; for client work, log settings and keep originals. When high ISO noise couples with motion, mild denoise before kernel estimation can stabilize direction finding, but over-denoise erases the cues the solver needs.
Motion deblur steps
- Inside `motion-blur-correct`, decide if blur is roughly linear or shows rolling-shutter skew—skew may need geometry fixes or a different frame.
- Read wheels, railings, and jersey type for broken strokes or double contours.
- If one frame is extreme but neighbors are cleaner, prefer the cleaner frame for anything archival.