How We Check
LensFinder.org is first and foremost a database: more than 1,400 lenses for 11 camera mounts, each with its technical data, searchable and comparable. This page explains where the data comes from, how we check it and what we deliberately do not do.
Where the data comes from
All technical data comes from the manufacturers themselves: product and specification pages, press releases, data sheets, instruction manuals and the archive pages for discontinued models. We do not take values from retailers, review sites, forums or other databases, not even for single specifications. The manufacturer pages behind a lens's data are linked on its lens page.
A lens that is made for several mounts has its own entry for each mount. That way weight, length and image circle match exactly the version that fits your camera.
How we check
Every record goes through fixed checks: the focal length and aperture in the name must match the fields, the number of elements must be at least the number of groups, and units and value ranges must be plausible. If a stored value differs from the manufacturer's specification, the manufacturer's figure wins. We are re-checking older entries against manufacturer sources step by step.
If a manufacturer does not state a value, we do not make one up. The field stays empty.
Facts, not reviews
We do not test lenses and we do not give scores. The texts on the lens pages put the specifications in context: who a lens is meant for, how it differs from alternatives in the same system, and which pros and cons follow from the data. Statements about image quality only appear when the manufacturer makes them, and then explicitly as the manufacturer's claim.
News and guides
On the blog we cover newly announced lenses. The same rule applies there: facts, prices and images come from the manufacturer, and we do not pick up rumors or teasers. There are also a few guides on topics such as mounts, sensor formats and lens types.
Tools
Automated tools, including AI models, help us collect the data and write the texts. Every figure still has to trace back to a manufacturer source, and the checks run across all entries.
Found an error?
Use "Report an error" on any lens page to point out a wrong value, or suggest a lens that is missing. We check every report against the manufacturer sources, usually within a few days, and correct or add the data.
Affiliate links
The price buttons lead to Amazon. If you buy through such a link, we receive a commission, and the price does not change for you. Which lenses are in the database and what we write about them does not depend on it.