DxOMark image quality testing protocols for lenses and sensors
A detailed look at DxOMark's image quality testing protocols, including laboratory conditions and setup, methods, test-specific tools, and software that DxO Labs developed and uses to ensure scientific, bias-free data and repeatable results.
DxO Labs has been measuring image quality parameters for a broad range of digital cameras and lenses (DSLRs, compact DSCs, cameraphones) for many years. To ensure that our measurements were accurate, repeatable, and covered the desired range of image quality parameters, we developed DxO Analyzer, now the world's leading tool for accurate and reliable image quality performance measurement. All published DxOMark measurements have been made using DxO Analyzer.
DxO Analyzer includes the following three key elements:
- A dedicated camera testing lab specifically equipped with dedicated test targets, lighting systems, light-boxes, light-meters, telemeters, spectrometers, etc.
- A set of precisely-described and bias-free test protocols for each measurement category which:
- Strictly accounts for all physical parameters that influence measurements.
- Ensures repeatability of the measurements.
- Software that automatically analyzes test target images, performs quality controls, and reports all measurements in graphic and data formats.
The basic protocol for all measurements is:
- Adjust test targets, lights, and the selected camera and lens.
- Shoot a set of images of the target at different camera and lens settings.
- Process the target images with DxO Analyzer (machine vision algorithms enable automatic processing).
- Evaluate the data and graphs reported through the DxO Analyzer interface.
Read more about DxO Analyzer.
DxOMark measurements are performed on cameras and lenses that are bought or rented from retailers. It is DxO Labs’ policy to test and publish results for publicly-available versions of each camera, rather than for cameras lent by the manufacturer or for pre-series models.
To eliminate setup bias, settings, instrument calibration, light levels, cleanliness (including that of the camera and lens), and all other parameters are checked and rechecked before each camera/lens is tested to ensure that all cameras and lenses are tested under exactly the same conditions.
Finally, each measurement is validated by at least two technicians who take their measurements on different days to minimize the risk of manipulation errors.