Este texto extraído de la web que enlazo creo que aclara y da la razón a las conclusiones que algunos de nuestros capos en matemáticas han ido sacando a lo largo del este hilo:
Quality of the analog-to-digital converter (ADC) and its read speed
Similar to the race to higher megapixels and the need to keep digital noise at bay, there is tension between the need for higher frame rates and the higher image quality gained by giving the
ADC more time to collect data from the sensor.
As usual, manufacturers are working towards doing both. The quality available from medium-format sensors is partly due to their slower frame rates (in some cases by a factor of 10).
The extent to which your photography requires high frame rates will factor into your speed vs. quality equation. The ADC also determines the sampling bit depth, as it converts the analog voltage to luminance levels. The ADC needs to be matched to the dynamic range of the sensor, thus defining the sensor bit depth for a camera.
Sensor bit depth (8-bits, 12-bits, 14-bits, 16-bits)
The trend has been to increase
bit depth from the 8 bits available in JPEG capture to 12 bits, 14 bits and even 16 bits. Newer DSLR cameras have progressed from recording raw data with 12-bit tonal gradation to 14-bit tonal depth. Most medium-format sensors record 14-bit depth data with some claiming 16-bit depth. The question is whether higher bit depth translates into higher image quality.
First we should dispel the myth that higher bit depth translates into higher dynamic range. It does not. Dynamic range is determined by the sensor's ability to read very low brightness as well as very high brightness levels. High bit depth slices the data more finely, but does not increase the ratio between the lowest and highest brightness levels a sensor can record.
Since 12-bit data has 4,096 tonal levels and 14-bit data has 16,384 tonal levels, one might expect to see smoother tonal transitions and less possibility of posterization with 14-bit capture, both of which would result in higher image quality. However, this is currently not the case for most 14-bit cameras due to the fact that digital noise overwhelms the extra bit depth. Slicing the data more finely than the level of noise means that the extra bit depth doesn't contribute to image quality.
Another factor that keeps us from realizing extra image quality from a 14-bit sensor as opposed to a 12-bit sensor is that most current DSLR cameras have less than 12 stops of dynamic range. Unfortunately, this makes the extra bit depth superfluous data. There are some exceptions. Fuji cameras employ two sets of pixels of differing sensitivity that allow for spanning more than 13 stops, so 14-bit depth is useful in that case. The latest Sony sensors, used in Nikon, Pentax and Sony cameras, have very low noise levels and high dynamic range and so are close to being able to generate genuinely useful 14-bit data.
As sensor technology continues to evolve, lower noise levels and greater dynamic range promise to make high bit depth capture a useful feature in future cameras.
For more information about noise, dynamic range and bit depth, see:
Noise, Dynamic Range and Bit Depth in Digital SLRs -- page 3
www.dpbestflow.org
