E-M5 has DR 13!

Started Apr 13, 2012 | Discussions thread
dotborg Veteran Member • Posts: 8,251
Re: Output Dynamic Range Specifications are limited by ADC Bit Depth

cmorse wrote:

I think what hes saying is that if you're only allowed ten numbers you could write

1, 2, 3, 4, 5, 6, 7, 8, 9, 10
1, 3, 5, 7, 9, 11, 13, 15, 17, 19

You still have the same number of pieces of data but have spread them over a greater range.

Of course in an image if you did something as simple as that you'd end up with some pretty ugly posterization. With a longer sequence of numbers though they might come up with something clever that extends the range a bit but is subtle enough that the gaps aren't overly noticeable. No idea or if they've done any such thing though.


From what I understand, the photo-sites of a CMOS sensor (yes, I know that the sensors used in m4/3 cameras are not strictly CMOS) are charged with +3.3v. The photons bombarding the photo-site then replenish the electrons, reducing the charge to zero. Therefore, the pre-amplification voltage range is +3.3v - 0v. The dynamic range of a sensor is determined by the capacitance of the photo-site and the noise of the circuitry rather than the number of bits it's encoded to at the AD converter. Depending on the capacitance, a photo-site could record 10 stops with that 3.3v range or 15 stops.

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