70D Dynamic Range is actually great, despite what DXOMark says

Started Jan 21, 2014 | Discussions thread
David Hull
David Hull Veteran Member • Posts: 6,387
Re: Noise reduction before raw file is written??????????????????

TTMartin wrote:

Tourlou wrote:

Where did you take this information? I want your references. By definition, a raw file is a map of the electron count of each photosite, not pixel. What can be applied by the manufacturer, is a correction of the luminance value per pixel to cover for manufacturing variations. The other map that's applied to a raw file is the defective (dark/hot) pixel correction. I never read anywhere that a noise reduction is applied at the raw file level.

Sony.net - Ultrahigh-Speed High Picture Quality CMOS Sensors Using Column-Parallel A/D Conversion

'The article presents the high-speed imaging technology based on column-parallel A/D conversion and the noise reduction technology used in this device.'

Anyway, this would not correct the shown images. The blacks are not black on lifted images. The image is fulle of read out/ dark noise. Maybe because of hot weather or a hot sensor (use of live view ).



People shouldn't get confused about noise reduction.  This article is comparing two different methodologies for implementing a signal processing function called the Correlated Double Sampler or CDS.  This bit of HW subtracts off the residual voltage that remains in the pixel diode when the sensor is cleared for a new image.  This means that the number reported as the RAW pixel value is strictly representative of the photons that were counted and not influenced by residual charge.

Both Canon and Sony have this feature, Canon uses an analog storage capacitor and Sony uses a count down digital ramp and a single bit ADC.  If there were significant differences here, there would be differences in the base read noise of the sensor itself.  Looking at the Sensorgen results we see that the best Canon designs are easily equal to anything Sony makes in terms of read noise so I don't think that the CDS is the problem (despite Sony's marketing pitch).

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