The noise-based speed is defined as the exposure that will lead to a given signal-to-noise ratio on individual pixels. Two ratios are used, the 40:1 ("excellent image quality") and the 10:1 ("acceptable image quality") ratio. These ratios have been subjectively determined based on a resolution of 70 pixels per cm (178 DPI) when viewed at 25 cm (9.8 inch) distance. The signal-to-noise ratio is defined as the standard deviation of a weighted average of the luminance and color of individual pixels. The noise-based speed is mostly determined by the properties of the sensor and somewhat affected by the noise in the electronic gain and AD converter.
The noise - based speed is defined as the exposure that will lead to a given signal - to - noise ratio on individual pixels . Two ratios are used , the 40:1 ( " excellent image quality " ) and the 10:1 ( " acceptable image quality " ) ratio . These ratios have been subjectively determined based on a resolution of 70 pixels per cm ( 178 DPI ) when viewed at 25 cm ( 9.8 inch ) distance . The signal - to - noise ratio is defined as the standard deviation of a weighted average of the luminance and color of individual pixels . The noise - based speed is mostly determined by the properties of the sensor and somewhat affected by the noise in the electronic gain and AD converter .
Which ratios are employed to calculate noise-based speed?
Which ratios are employed to calculate noise - based speed ?
the 40:1 ("excellent image quality") and the 10:1 ("acceptable image quality") ratio
the 40:1 ("excellent image quality") and the 10:1 ("acceptable image quality") ratio