Sensors often eliminate particular kinds of fixed pattern noise (e.g., row and column noise, hot and dead pixels). This is greatly beneficial to the image and presents essentially no drawbacks. At very high ISOs, however, some manufacturers apply a more systematic noise reduction filter to eliminate noise at pixel level. In this case, the gain can be objectionable: there is indeed an increase of SNR in homogeneous areas, but it is not likely that this noise reduction will be as elaborate as RAW converter noise reduction on textured areas with fine details. Moreover, RAW converters will get better over time, whereas noise reduction on the sensor itself will continue to definitively eliminate some information and thus affect detail resolution.
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The Sony Alpha 700 with its new version 4.0 firmware scored a 66.3 on the DxOMark Sensor scale, putting it in 17th place on the dxomark.com overall ranking, and in 5th place for APS-C cameras. Given its launch date (Sept. 2007), this is a pretty good result.
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The dxomark sensor scale is based on RAW data measurements and provides comparable metrics only if no RAW-specific processing has been applied.
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The DxOMark Sensor scale is based on RAW data measurements and provides comparable metrics only if no RAW-specific processing has been applied.
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