Lens Selection Standards for Camera TestingBy: John Honovich, Published on May 15, 2011
With surveillance cameras, deciding what lenses to use for testing can be a difficult decision. We see two basic yet fundamentally opposing approaches:
- Use the same lens on every camera tested: This approach ensures that no camera has an unfair lens advantage, allowing the test to focus on the camera's own performance.
- Use the manufacturer recommended lens for each camera: This approach ensures that each camera uses the typical production lens, allowing the test to show real world use.
We use and recommend the second approach - testing with the manufacturer recommended lens for each camera. Here's why:
- Many cameras have integrated lens: most domes, cube and bullet cameras as well as box cameras with built in optical zoom. For cameras with integrated lenses, it is simply impossible to use the same lens on every camera.
- Many box cameras that allow for interchangeable lenses ship with a standard lens (e.g., Axis, Sony, IQ, IndigoVision, Mobotix, etc.). These manufacturers treat lenses as a core component of their camera system. If we used a different lens, this would be unrepresentative of the experience (good or bad) of regular users.
- Even manufacturers that do not ship box cameras with lenses (e.g., Arecont Vision, Pelco Sarix), generally have recommended lenses that they sell and that many, if not most, of their users choose. In this scenario, we use the lens that the manufacturer recommend / sells.
- If we did use the same lens on every camera (for cameras where this is possible), criticism would still exist as industry people would differ on the quality of the 'standard' lens chosen in our test (e.g. we used Lens Brand X but they prefer Lens Brand Y).
Our philosophy is to mirror real world use as closely as possible. To that end, using lens provided and/or recommended by the manufacturer is the best way to do this.
Indeed, it would actually be easier and cheaper to simply buy 10 lenses of the same brand/model and use them for every test. However, we are confident that this would result in increased criticism and concerns over the validity of the tests.
Given the differing approaches of manufacturers for lens provision, we do not think it is possible to reconcile or appease proponents of both approaches. On balance, we believe using the manufacturer recommended lens is the best approach for providing realistic comparisons.