What LTX-2.3 Fast is good at — and what it's not

LTX-2.3 Fast is the faster, lower-cost image-to-video tier of LTX-2.3. It keeps what makes LTX distinctive: animate a start frame outward, with native 4K output (up to 2160p) and keyframe interpolation when you add an end frame. The lower cost means you can iterate on animated shots more freely than the Pro tier allows, while still being able to deliver true 4K.

Clips run 6, 8, or 10 seconds with native audio on by default. Product reveals, controlled transitions, and animating generated stills are the natural fits — and unlike most tiers, you can finish at 4K rather than relying on a separate upscale.

Where it sits: LTX-2.3 (the Pro tier) targets higher fidelity; LTX-2.3 Extend continues an existing clip rather than animating a still. For image-to-video in other lines, Wan V2.6 Flash and Hailuo 2.3 Fast are options. LTX-2.3 Fast's sweet spot is affordable, 4K-capable image-to-video.

A reasonable mental model: default to LTX-2.3 Fast when you're animating a still, want 4K, and value cost and iteration, and step up to the LTX-2.3 Pro tier for peak fidelity on a final.