Hyperbolic wedge refers to features on the resolution test chart for quickly and more reliably assessing the limiting optical resolution visually. This approach greatly enhances imaging performance diagnostics to measure lens blur, sharpening and potential aliasing. Spatial frequency response (SFR) refers to the use of a slanted-edge gradient technique for capturing a super-resolution edge profile and transforming this into a spatial frequency signature. The protocols in this standard debunk the use of pixel count (megapixels) as a representation of camera resolution.

The first edition, issued in 2000, provided a scientifically sound and easily accomplished standard way to measure the true optical resolution performance of any digital camera image of the test target shown above. ISO/TC 42 has revised ISO 12233, now ISO 12233:2014, Photography - Electronic still picture imaging - Resolution and spatial frequency responses, with methods for measuring the resolution and the Spatial Frequency Response (SFR) of digital cameras. Camera resolution test chart from ISO 12233:2000

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