Two hand-held DSLR shots of a similar camera move are combined together using the Furnace Align plugin in Nuke. F_align uses global motion estimation to translate, rotate, scale, and cornerpin one plate to a reference plate.
It's like shooting motion control with a handheld shot that would be impossible to repeat.
- Acquire footage using a similar handheld camera move. Talent takes care to make the point of interaction between clips the same.
- Determine temporal alignment of talent interaction (moment of impact) and offset frame sequences in time appropriately so that these frames line up.
- Apply f_align plugin in Nuke.
- Roughly rotoscope talent in clip B and merge on top of clip A.
- Additional camera shake is added after the moment of talent interaction.
- Final audio acquired and added.
- These test shots were taken without any stabilization rig for the Canon 60D, which amplified rolling shutter artifacts on the footage. Alignment errors due to rolling shutter are evident and distracting when the aligned clips are places on top of each other. Given this source footage, a better approach would be to use a rolling shutter reduction plugin before alignment.