TIPA’s testing partners, Testlab, who handle camera testing, and DXOMARK, who deliver lens and, soon to be available, smartphone reports, are world-renowned labs with long experience in the measurement and appraisal of consumer electronics and photographic products. These reports are used by member publcations as part of their reportage on new and exciting gear that adds authoritative data and scientific test results to their equipment reviews.
Along with measurements and supplied charts covering a wide range of individual performance parameters, overall scores are assigned to each product tested based upon a weighting system that combines a number of test results. This allows readers to make purchasing decisions based on their budget, photographic interests, and the study of comparative performance results.
In the case of camera testing, TIPA’s scoring system and scope of measurements has changed from previous years. Our new laboratory, Testlab, uses equipment from our former testing partner, Image Engineering, thus maintaining continuity of measurements. In 2021, the TIPA camera score was improved to be a dual score composed of a still photography portion and a video component. This dual score remains.
However, Testlab does not perform speed tests or OECF (including dynamic range) measurements. As a consequence, the weighting of the score components has been adjusted in the current score based on sub-scores for image quality (lab measurements), a practical handling evaluation, and evaluation of the technical specifications.
The video score comprises three elements: image quality (of frames grabbed from movies made under controlled conditions), video handling, and video specifications. It should be noted that the cameras used for TIPA reports are provided by the manufacturers as test samples and that lenses used are a ‘best quality’ lens, usually a prime.
For lens testing, DXOMARK mounts the lens on cameras capable of delivering RAW format images. Each component of the tests is later combined to deliver an overall score, which then can be used as a comparative with other lenses in the same price range, focal length and aperture range. The resolution score represents the sharpness performance of a camera combination averaged over its entire focal length and aperture range. As a practical measure, DXOMARK uses the measured MTF to compute the highest print size that keeps an acutance of 80% when viewed from one meter away and considering the whole field of view.
Other tests include measurement of lateral chromatic aberration; vignetting (at each focal length, in the case of zooms, at the widest aperture); distortion (barrel and pincushion); and light transmission (and its effect on exposure times and possible need for higher ISO settings).
The DXOMARK Lens Score corresponds to an average of the optimal quantity of information that the camera can capture for each focal length. The quantity of information is calculated for each focal length/aperture combination and the highest values for each focal length are weighted to compute the score. It should be noted that the score is based on low-light conditions (150 lux and 1/60s exposure) and that it does not account for depth of field and only considers lens performance at perfect focus.
Member and Reader Benefits
Each month, TIPA will provide test results from its partner labs to its member publications in the hopes that this information will both add to their authoritative reporting and help educate their readers about the latest photographic and imaging products.