The world's first expert system dedicated to photographic lenses

lens-db.com was founded on July 06, 2012 by Evgenii Artemov and was originally created as a regular photographic lens database. Over time, its creator developed an understanding that it is not enough just to provide website visitors with general information about a particular lens - it is necessary to help choose the most suitable lenses for certain genres of photography and explain why it is advisable to opt for them. In addition, it is necessary to simplify the selection process as much as possible, without the need for the visitor to manually go through tens or even hundreds of lens models in the database. And, of course, it became clear that the extensive database formed over the years of the website's existence, along with expert experience, allows not only providing users with comprehensive information about a particular lens, but also giving advice on the choice and effective use of lenses, compare and evaluate them according to certain rules, without shifting this task to the visitors themselves.

This is how our website evolved into an expert system.

Expert system is a computer program that uses artificial-intelligence methods to solve problems within a specialized domain that ordinarily requires human expertise. Structurally, the expert system consists of a knowledge base, an inference engine and an user interface. A knowledge base is an organized collection of facts about the system's domain. Facts for a knowledge base come from human experts and are usually presented in the form of "if - then" rules that can be applied to known facts to generate new facts. The inference engine interprets and evaluates facts in the knowledge base to provide an answer. Expert systems do not replace human experts, but serve as additional aids.

Today our website fully meets all the requirements for an expert system.

Thanks to the hard systematic work, the website's knowledge base includes photos, model history, camera compatibility information, specifications and descriptions for 4108 autofocus and popular manual focus interchangeable lenses designed for SLR, rangefinder and mirrorless cameras: from APS-C to medium format 6x9cm, from fisheye to super telephoto lenses.

It is not our goal to record as many lenses as possible in order to make the database the largest in the world. In our opinion, QUALITY, UNIFORMITY AND ACCURACY OF INFORMATION, as well as conclusions based on it, are much more important than QUANTITY OF INFORMATION.

Unfortunately, being guided by this principle, we cannot entrust the users of our website to modify the database.

The facts in our knowledge base come from two main sources:

All this makes our knowledge base the world's largest credible.

Note: since the website is an expert system and not a test lab, we don't have lens tests and reviews here.

The website's inference engine solves the following tasks:

  • determines if the lens can be classified as a so-called pancake lens,
  • determines if the lens belongs to the so-called "Holy Trinity" of lenses and displays a list of lenses included in it,
  • finds the pros and cons of lenses and provides the user with information in a convenient way,
  • compares lens specifications and provides the user with information in a convenient way,
  • finds alternatives for a particular lens,
  • finds best-in-class lenses,
  • determines which genres of photography the lens suits best and gives advices on how to use it,
  • determines if the lens belongs to professional models,
  • allows you to choose a suitable lens by the genre of photography and a camera you plan to shoot with,
  • evaluates the completeness of lens lineups for enthusiast and professional photography, finds similar lens lineups.

Most of these tasks are solved using a set of heuristic rules, or "rules of thumb", and not simply based on focal length and speed of lenses.

Other useful features of the website include:

  • The knowledge base contains a complete list of lenses ever produced by system camera manufacturers. At the same time, manufacturer websites usually list only those models that are currently available for purchase, and information on discontinued models may be scarce or even absent.
  • The website automatically decodes abbreviations used by manufacturers in the lens names, so you don’t need to consult various "lens abbreviation tables" available online or remember specific abbreviations by yourself.
  • Thanks to the website’s built-in help system, when viewing the lens specification you don’t need to google what are the advantages of Lead-screw type Stepping Motor, what does "MO" stand for in the Sigma [AF - MO - MF] focus mode selector name, and how Mode 1 of the optical image stabilizer differs from Mode 3. And of course, the possibilities of the website’s help system are not limited to the mentioned above examples.

Thus, as you can see, our website has no competitors: on the one hand, there are ordinary databases dedicated to photographic lenses, and on the other hand, there is lens-db.com.

Our website is an independent non-commercial project: we are not affiliated with any photographic equipment manufacturers or commercial organizations and work out of love for art, not for money.

The website is absolutely free, and intended for a wide range of visitors, whether they are beginner photographers or honored masters, amateur photographers or professionals. Registration is not required.

You, as a visitor, may:

  • leave your feedback on lenses you used in the past or use now,
  • inform us about errors in specifications, lens descriptions or website engine,
  • donate money for maintaining the website,
  • advertise your products, works and services directly related to photography.

And, of course, share links to our website on social media, if you believe that our website is really useful and deserves that as many people as possible should use it.

Our ongoing tasks:

  • Maintain the website until the photographic technologies to which the website is dedicated remain relevant and users are interested in receiving information about them;
  • Improve the knowledge base: find and fix errors (if any), add descriptions and missing information, add new lenses announced by manufacturers;
  • Improve website design and presentation of information from the knowledge base.

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Copyright © 2012-2021 Evgenii Artemov. All rights reserved. Translation and/or reproduction of website materials in any form, including the Internet, is prohibited without the express written permission of the website owner.