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Motion / Zoom Blur

Fakes a moving camera or a zoom during the exposure. Blur only the background for a panning look, or streak the frame toward a centre point.

Motion / Zoom Blur — before, motion 60 px on the background only, zoom 0.15
In ComfyUI Add Node → ComfyUI-JH-PixelPro → filters → Filters: Motion / Zoom Blur
Good for Panning shots, speed effects, zoom bursts, adding energy to a static background
Speed At 4K on a GPU: motion 200 px about 1.4 s, zoom about 0.1 s, under 1 GB VRAM.

When to use it

  • motion averages the picture along a straight line, like a camera or subject moving during the exposure. Set the direction with angle and the length with distance.
  • zoom averages along the rays toward a centre point, like turning the zoom ring during the exposure. Pixels near the centre barely change; the frame edge streaks the most.

For a panning look, blur the background only. Connect an inverted subject mask to mask: the blur applies where the mask is white.

Quick start

  1. Load Image → Filters: Motion / Zoom Blur → Preview Image.
  2. Motion: set mode to motion, angle 0 for a sideways streak, and try distance 60.
  3. Zoom: set mode to zoom and keep zoom at 0.15, with the centre at 0.5 / 0.5.
  4. Optional: connect an inverted subject mask to mask to keep the subject sharp.

Settings

Setting Default What it does Tip
mode motion motion = blur in one direction. zoom = streaks toward a centre point.
angle 0 -180 to 180 degrees. 0 = horizontal, 90 = vertical. Used by motion only. Match the direction the subject moves.
distance 20 0 to 1000 pixels. Blur length for motion. Scale it with image size: 60 px at 2K is subtle, 200 px at 4K is strong.
zoom 0.15 0 to 0.9. The frame edge streaks over this fraction of its distance to the centre. Used by zoom only. 0.1 to 0.3 looks natural.
center_x, center_y 0.5, 0.5 0 to 1. Where the zoom streaks point to, across and down the frame. Used by zoom only. Put it on the subject's face or eye.
mask (optional) none Blur only where the mask is white; elsewhere the image is unchanged. Use an inverted subject mask.

Output

Output What it is
image The blurred image, same size as the input. motion with distance under 0.5, or zoom of 0, returns the input unchanged.

Tips from retouching

  • Pass the subject mask through Mask Combine (invert) and soften its edge with Mask Edge Smoother so the sharp subject does not show a hard rim.
  • Blur first, then add Smart Sharpen to the subject only.
  • Very long distance on a busy background becomes a smear. Raise it gradually.
  • Move center_x and center_y onto the subject for a zoom burst that pulls the eye in.
Under the hood

Both modes are a box blur along a one-dimensional path. A box of n1 × n2 taps is the same as a box of n1 taps at spacing 1 followed by one of n2 taps at spacing n1, so a blur D pixels long needs about 2·√D warps instead of D. Zoom uses the same trick in log-radius, where scalings add up. Each warp is a bilinear grid_sample with reflection at the borders, and the average keeps the overall brightness. Memory stays proportional to the number of pixels. ComfyUI hands images over on the CPU; the node moves the work to the GPU when one exists and falls back to the CPU on out-of-memory. The optional mask blends the result with the original. Source: core/directional_blur.py.

Example workflow

Motion / Zoom Blur example workflow shows the motion blur on the background only and the zoom burst. Copy workflows/sample_portrait.jpg and workflows/sample_binary_mask.png into ComfyUI/input/.