FAQ

We don't add to the database:

• lenses designed for formats other than medium format, 35mm full frame or APS-C,
• pre-WWII lenses, except for Leica screw mount lenses,
• vintage lenses with aperture controlled from the camera body only, including but not limited to: Deckel (DKL) and Topcon UV mount lenses,
• lenses with external automatic diaphragm, including but not limited to: lenses with Exakta mount, Tokyo Kogaku Auto-Topcor lenses, Miranda dual mount lenses with Pressure Automatic Diaphragm,
• lenses with Alpa, Altix, Bronica Classic, Canon J (+ Nippon-Kogaku focusing mount), Contax RF, Olympus OM AF, Pentacon Six, Petri, Practica B, Voigtlander Prominent, Yashica AF, Yashica Pentamatic mounts,
• lenses of little-known brands, including but not limited to: Acall/Kyoei, Access, Accura, Albinar, Asanuma, Beroflex, Berolina, Bower, Cambron, Carena, Centon, Chinon, Computar, Cosmicar, Danubia, DeJur, Elicar, Focal, Formula 5, Hanimex, JC Penny, Kaligar, Kalimar, Kawanon, Kenlock, Kobori, Komine, Lensbaby, Lomography, Makina, Old Delft, Opteka, Optomax, Osawa, Ozeck, Pallas, Panagor, Paragon, Pentor, Petri, Phoenix, Photax, Porst, Prinz, Pro Optic, Promaster, Promura, Quantaray, Revuenon, Rokinon, Sakar, Samigon, Sears, Sirius, Soligor, Spiratone, Starblitz, Sun, Sunagor, Tefnon, Telesar, Tou/Five Star, Unitor, Universar, Upsilon, Varexon, Vitacon, Vivitar (non Series 1), Walimex, Weltblick, Wollensak,
• Cosina manual focus lenses (before the company began to use the Voigtlander brand), Kiron manual focus zoom lenses, Sigma manual focus zoom lenses, Sigma-XQ lenses, Sigma YS lenses, Tokina manual focus lenses (due to inconsistencies in specifications in the company's materials over the years and release of versions with different optical formulas under the same name), Rikenon P manual focus zoom lenses for the Ricoh K mount (as most of them were rebranded lenses from such third-party manufacturers as Cosina, Sigma and Tokina),
• lenses made by the following German manufacturers: A. Schacht München/Ulm, Carl Zeiss Jena, Enna München, Isco (Optische Werke) Göttingen, Meyer-Optik Görlitz, Pentacon Dresden, Rodenstock München, Steinheil München,
• Soviet/Russian lenses, including but not limited to: Granit, Helios, Industar, Jupiter, Kaleinar, Mir, Peleng, Rubinar, Russar, Tair, Telear, Telemar, Vega, Volna, Yantar, Zenitar, Zodiak,
• Chinese lenses (not gonna even bother making a list of brands),
• lenses developed for military applications (for example, ELCAN lenses made by Ernst Leitz Canada for U.S. Navy),
• CCTV, projection, cine, stereo, enlargement, microscope lenses,
• lenses designed for use with reflex housing (Canon Mirror Box, Leica Visoflex, etc.),
• autofocus lenses designed for manual focus cameras,
• body cap lenses,
• attachment lenses,
• teleconverters, telecompressors,
• prototype lenses.

Because of the small sensor size, Micro 4/3 cameras compete with compact cameras with non-interchangeable lenses rather than with APS-C or 35mm interchangeable-lens cameras. Given the fact that our database records lenses designed for APS-C or larger sensors, Micro 4/3 system cannot belong to our database. The same is true for the 4/3 SLR system.

We do not use unverified private information. At our website, lens specifications are unified and filled out only on the basis of data contained in brochures or operating instructions published by lens manufacturers. That's why we don't have to sync with any websites, except for lens manufacturers websites, of course.

We do not believe that ratings can reflect an objective view of a particular lens. Any assessment is always subjective and often does not take into account the whole complex of factors that have a significant impact on performance of the lens.

In particular:

• The sharpness of the final image depends on the combination of camera and lens used. In addition to focal length and aperture, sharpness can also be affected by focusing distance: conventional lenses are optimized to provide the best image quality when focusing at infinity, and therefore may exhibit reduced image quality at short to medium distances;
• The bokeh depends on the DISTANCE between the camera and the subject (the smaller it is, the more the background is blurred), as well as the DISTANCE from the subject to the background (the larger it is, the more the background is blurred);
• The autofocus performance of a lens depends on factors, not all of which are directly related to the lens itself: available lighting, autofocus algorithms used by the camera, contrast of the subject, focusing distance, and much more;
• The resistance to flare depends on whether the original lens hood is used with the lens.

Are you sure that users who rate lenses on other websites are aware of all these factors and are taking any careful account of them?..

Sorry, but we do not collect this kind of data. We do understand that sometimes serial numbers are important and useful (especially in the case of Nikon and Leica lenses), because they can help to distinguish one variant of the lens from another, or roughly determine the year of production. Anyway, currently we do not have any plans to record sets of serial numbers in our knowledge base.

No, we don't sell anything. Nevertheless, there can be links on the pages of our website to online stores or private sellers of photographic equipment, which we consider reliable and whose services we often use when we want to purchase photographic equipment.

Sometimes users of our website have been questioning us in the comments about original or current market prices of certain lenses. Typically, these questions are due to the fact that such users plan to sell lenses on marketplaces (for example, eBay).

Please be informed that our website specializes solely in providing information on lens specifications and descriptions. Moreover, the website is non-commercial: we do not sell lenses or track their prices and do not provide users with the opportunity to place advertisements for the sale of lenses. It's just not interesting to us. Therefore, we cannot help you determine the original or current market price of a particular lens.

Besides, such questions seem to appear on our website due to the fact that there is an online database of current market prices of popular autofocus and manual focus lenses with a similar name lens$db: http://www.jcolwell.ca/photography/lens$db/index.htm

With this in mind, for all questions related to determining the price of a particular lens, please refer to the mentioned above website.