Methodology & sources
Three rules: every spec is taken from a published source and recorded, every page is dated, and nothing is invented.
Sources
- Manufacturer product catalogs (Sony, Canon, Nikon, Fujifilm, Sigma, Tamron) — focal length, maximum aperture, mount and coverage are taken from official product names and spec sheets.
- We deliberately do NOT store prices — they change; check the retailer at purchase time. Lens weights, where shown, are the maker's published figure (weight is fixed at manufacture): from the manufacturer's own spec page where we have it, otherwise from a published lens database or review quoting that figure. Every weight carries a per-lens source in the dataset, and each weight table says how many of its rows came from which. A lens without a verified weight is omitted from the table, never estimated.
- Our catalogues list every lens that mounts on a system, including models no longer in production. A fit reference is most useful when it also covers the lens you already own or found second-hand — so we do not track retail availability, and a listing here is not a claim that a lens is still sold new.
What we never do
- No invented "ratings" or review scores — groupings reflect focal length and aperture facts, not opinions.
- No sponsored placements.
- No stale data presented as fresh — every page carries a "last verified" date.
Corrections
Spotted an error? Contact us with a link to the manufacturer page; corrections ship within days.