Deliberately omitting frames during capture or editing — for time-lapse, stop-motion, or to save render time. Don't confuse with dropped frames.
You're filming a construction site over three weeks and want to condense the material into 30 seconds — this is where skip frames come in. It's about the systematic omission of images, either directly during recording or later in the edit. Unlike dropped frames, which arise from technical errors, skip frames are a conscious, calculated decision. The camera captures every image, but you only take out every fifth, tenth, or hundredth — depending on the desired time-lapse effect.
On set, this classically works via interval recording: the camera shoots one frame every X seconds. With stop-motion, this is standard anyway — you photograph the figure, move it two centimeters, photograph again. The result appears fluid, even though hours can lie between the images. For live-action time-lapse, you also set the camera to interval: one frame every 2 seconds at 24fps results in a 48x time-lapse. The calculation is simple: the greater the distance between the captured frames, the faster the movement in the final edit.
In the edit, skip frames work differently: you already have full material and remove images afterward — deleting every fifth frame, for example, to accelerate movements or to save rendering load. This can be useful with 4K material: instead of editing at full resolution, you temporarily work with skipped frames to keep the timeline fluid. This saves CPU resources without you having to render a separate proxy version. However: the result is not identical to true time-lapse. Skip frames create a slightly jerky quality — some movements appear like slight stop-motion moments. This can be intentional (dystopian look) but quickly appears clumsy if it happens unintentionally.
The biggest pitfall: confusion with defective material. Dropped frames arise from errors (full hard drive, bad codec setting), skip frames are your intention. Quality control is essential — watch the preview before you delete material. For stop-motion and pure time-lapse effects, skip frames are indispensable. For narrative scenes, you should avoid it or only use it as a deliberate stylistic trick.