“Which video model is best?” is too broad for an advertising producer. One campaign may need to restyle a shot already filmed; another may need to invent a scene from scratch. Luma’s Modify workflows and Runway’s Gen-4 family show why those are not equivalent tasks.
Scope: Global English buyer context as of 25 October 2026; exact regional and plan access are not assumed. Evidence: Vendor documentation, not independent hands-on tests. Editorial status: ready.
Evidence at a glance
| Option or route | Source-backed observation or unresolved requirement | Evidence class |
|---|---|---|
| Luma Modify | Luma documents video modification and 2025/2026 reference controls | Official provider document |
| Luma Ray2 history | 2025 Modify documentation describes original-footage workflows | Official provider document |
| Runway Gen-4.5 | Runway documents image-to-video and text-to-video creation | Official provider document |
Choose the operation first
Luma documents Modify Video as a way to transform existing footage while aiming to retain the original camera and motion. Its December 2025 Ray3 Modify announcement emphasizes keyframes and character-reference controls. Runway documents image-to-video and text-to-video creation with its Gen-4 and Gen-4.5 systems. This comparison therefore begins with a fork: do you have a legally cleared master clip whose timing must survive, or only storyboard artwork and a shot brief?
When restyling is the primary objective
Imagine a studio has ten seconds of a model placing a product on a table. A motion-preserving transformation can be useful for exploring seasonal environments without reshooting the hand movement. But the original shot’s release must permit the intended downstream edits; editing a person into another context may need renewed approval. Inspect whether brand marks, fingers and prop geometry survive the transformation rather than being visually reimagined into an inaccurate claim.
When inventing the shot is the primary objective
For an unfilmed reveal shot, a text- or image-conditioned generator lets the director establish a new scene. Create an image reference showing the product from the correct angle, define the camera path and evaluate one shot at a time. A new generative sequence may save location work but can introduce continuity problems across adjacent shots. Rebuilding the same motion from scratch is a different risk than recoloring a previously approved performance.
Production acceptance tests
Assess three requirements independently: product identity, motion continuity and export quality. Give reviewers a blind montage containing the original and alternative versions. Ask them to flag inaccurate claims, changing label text and background geometry. Track how many seconds remain useful after conventional editing, not just how many seconds were rendered. No generated test videos or third-party quality ratings are claimed in this article.
Commercial and regional cautions
Identify which Luma and Runway model route was used and its permitted inputs, upload cap, output resolution, watermark and export rights. Luma’s 2025 Ray2 guidance should not silently be treated as a 2026 Ray3 contract; similarly Runway Gen-4 and Gen-4.5 have different published pages. Compare prices only after AI 10 has dated credit/second rates and a usable-output method. Producer consent and music rights are independent of model output rights.
Recommendation
If creative revisions must preserve photographed choreography, evaluate Luma’s documented Modify approach first. If there is no source shot and the campaign is conceived as a storyboard, include Runway’s image-input generation pathway. Many campaigns will use both classes of tool in different stages. The final vendor decision requires actual pilot footage, legal clearance and a named plan; no objective winner is asserted here.
Sources and Further Reading
- Luma AI: Introducing Ray3 Modify (checked 2026-10-25)
- Luma AI: Dream Machine Modify Video (checked 2026-10-25)
- Runway: Creating with Gen-4.5 (checked 2026-10-25)
Price, entitlements, regional access and rights change. This article does not invent a live subscription offer, comparative benchmark or hands-on result. For commercial purchasing, seek dated provider contracts and AI 10 normalized price snapshots.