Method — where every compatibility fact comes from

How this dataset is built and audited: every claim cites a verified source with a date, unsupported combinations are labeled rather than guessed, and the tool never fabricates a compatibility answer.

What this site is

LensCompat answers one question with evidence: does this lens work on this body, and what do I need to know? Today that means Canon RF and RF-S lenses mounted natively on EOS R bodies, EF-family lenses (EF, EF-S, TS-E, MP-E) on those bodies through the official adapter, Nikon Z and Z DX lenses mounted natively on Z bodies, and F-mount lenses (AF-S · AF-P · AF-I · screw-drive · AI-S) on Z bodies through the FTZ. The dataset is the asset; the lookup tool and these guide pages are views over it. Nothing on this site is a hand-written compatibility claim — every rendered verdict resolves through the same engine over the same versioned, source-cited dataset.

Provenance discipline

Every fact row carries source_ids; every source carries a verified URL (fetched, content read), a kind, and an accessed_at date.
Facts that could not be verified are never inferred to complete the dataset. The engine reports those combinations as unsupported_claim — explicitly.
If a fact changes, the new fact gets a fresh source row with a new verification date; old rows stay as the provenance trail.
A build-time validator (npm run validate) refuses to pass a dataset whose rows lack sources or reference unknown source ids, and smoke-tests every lens × body combination for claim coverage.

Source kinds

Kind	Count	Meaning
`official`	282	manufacturer-published (Canon / Nikon product pages, support documents, press, museums)
`consensus-third-party`	10	respected review / spec references (e.g. DPReview)
`manufacturer`	0	other manufacturers (adapter makers)
`community`	0	forums and community posts — lowest confidence, still citable
`retailer`	138	retail listings (Amazon product pages) — referenced for product identity (the ASIN ledger), never as compatibility evidence

Current dataset

Collection	Rows
Sources	430
Camera bodies — RF · full-frame	12
Camera bodies — RF · APS-C	5
Camera bodies — Z · APS-C	4
Camera bodies — Z · full-frame	9
Lenses — EF · full-frame	49
Lenses — EF · APS-C	10
Lenses — RF · full-frame	46
Lenses — RF · APS-C	7
Lenses — Z · full-frame	42
Lenses — Z · APS-C	7
Lenses — F · full-frame	35
Lenses — F · APS-C	5
Official adapter families	2
Class rules	6
Caveats	4

Dataset sources last verified 2026-09-10. The full source ledger is public on the sources page.

Honest limits

Corridor-bounded. Declared corridors — RF lenses mounted natively on RF bodies; Z lenses mounted natively on Z bodies; EF lenses on RF bodies via the Mount Adapter EF-EOS R; F lenses on Z bodies via the Mount Adapter FTZ. Any combination of other mounts returns no claim, never a guess.
Effective crop resolution is body-dependent and not stated in the sources we verified — the tool says so instead of estimating megapixels.
Per-lens mechanical specs (tilt/shift ranges, magnification, weights) are not yet in the dataset and are not claimed.
Verification is point-in-time: pages are cited with the date their content was fetched. A manufacturer could change a page after its accessed_at; re-verification adds a new source row.

Retailer links

Where a verdict needs a product, the tool offers an Amazon link (marked rel="sponsored", Associates tag lenscompat-20). Rows with a verified ASIN deep-link to that product page; everything else falls back to a search link. The compatibility answer never depends on the retailer links — they appear only after a verdict resolves, and the tool works fully without them.