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DxO Labs claims that P-MP is a more accurate and relevant value for photographers to consider when weighing-up camera sharpness. [ 2 ] [ 1 ] As of March 2017, the "Canon EF 300mm f/2.8L IS II USM" lens mounted on a "Canon EOS 5Ds R" has the highest measured P-Mpix value in the DxO Labs lens database, a value of 44.7. [ 3 ]
Imatest test charts include SFRplus, eSFR ISO, SFRreg, Spilled Coins, and 36-patch Dynamic Range targets. Imatest has been adopted by a wide range of industries that employ embedded digital imaging systems, including mobile imaging (camera phones), automotive, medical imaging, aerospace and machine vision , as well as publications/reviews, and ...
The DXOMARK Lens Score provides ratings for camera lenses, as tested using its proprietary tool-set in combination with various camera models. [8] [10] [17] As with the DxOMark Sensor Score, the DXOMARK Lens Score is an aggregation of five separate sub-scores; namely: sharpness, distortion, vignetting, transmission, and chromatic aberration.
System sharpness is affected by the lens (design and manufacturing quality, focal length, aperture, and distance from the image center) and sensor (pixel count and anti-aliasing filter). In the field, sharpness is affected by camera shake (a good tripod can be helpful), focus accuracy, and atmospheric disturbances (thermal effects and aerosols).
Visual acuity is a subjective test meaning that if the patient is unwilling or unable to cooperate, the test cannot be done. A patient who is sleepy, intoxicated, or has any disease that can alter their consciousness or mental status, may not achieve their maximum possible acuity.
The reverse, in which the perimeter is magnified more than the center, is known as "pincushion distortion" (figure 3b). This effect is called lens distortion or image distortion, and there are algorithms to correct it. Systems free of distortion are called orthoscopic (orthos, right, skopein to look) or rectilinear (straight lines). Figure 4
A 1951 USAF resolution test chart is a microscopic optical resolution test device originally defined by the U.S. Air Force MIL-STD-150A standard of 1951. The design provides numerous small target shapes exhibiting a stepped assortment of precise spatial frequency specimens.
A perfect lens system will provide a high contrast projection without shifting the periodic pattern, hence the optical transfer function is identical to the modulation transfer function. Typically the contrast will reduce gradually towards zero at a point defined by the resolution of the optics.
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