zhangyue Offline Upload & Sell: On
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kwalsh wrote:
The ADC isn't the problem, the pixel read circuitry and pixel well depth are the limits. All current cameras are not limited by a 14-bit ADC and only the very best Sony sensors even come close to needing 14-bit. Many cameras with a 14-bit mode are just for marketing purposes, the extra-bits serve no purpose at all.
Do the math, a 20-bit ADC won't do diddly. In fact, it is a completely senseless suggestion because even the deepest wells in the industry (Canon 1DX) are only 90,000 electrons. That would be 17-bits if you had a read noise of 1 electron (and you don't, read noise on the 1DX is over 30 electrons).
And to demonstrate how irrelevant the ADC typically is, the H3DII 50 has your lusted after 16-bit ADC and a dynamic range of 11 EV...
Big changes in DR are more likely to come from different sensor architectures. Fuji has done dual sensitivity pixels with some success - DR is certainly improved significantly but at a resolution cost. In the academic side very small 1-bit pixels hold promise as well, and they would naturally have a highlight roll-off as well.
Increasing ADC bit depth, however, isn't going to solve anything.
Ken...Show more →
+1, the bottle neck is not DAC, but sensor(ADC) itself. Now days, it is not hard to get even 24 bit DAC performance with DR more than 120dB.
The thing is if you don't need high pixel, but just pixsel quality, apply a LP filter in optical, and let camera to do the over sampling and noise shaping in digital domain, you could achiveve more DR with even existing sensor. But that is shrow away pixsel. And DR is really pretty good as is now
edit: ADC to DAC, I was on cell phone.
Edited on Mar 29, 2013 at 12:38 PM · View previous versions
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