----- Original Message -----
From: Larry Colen <[email protected]>
To: Pentax-Discuss Mail List <[email protected]>
Cc:
Sent: Tuesday, May 22, 2012 8:20 PM
Subject: Re: K-30 vs K-5
On May 22, 2012, at 3:43 PM, steve harley wrote:
> on 2012-05-22 11:31 Rick Womer wrote
>> I think another big difference will be the 12 v. 14 bit/channel RAW--I
>> suspect those extra bits in the K-5 are where the great DR lives.
>
> that concerns me too, but somehow dxomark rates the dynamic range of the K 01
> 12.9 Evs vs 14.1 Evs for K-5 — just over a stop of difference rather than the
> two stops that the data path would support, but still a significant difference
>
> (it would seem odd that 12 bits can support almost 13 stops of dynamic range;
> i suspect that some sort of dynamic range compression is used, or that i
> don't understand dxomark's measurement system)
I think that it can measure 13 stops of dynamic range, but with only 12 bits of
resolution. In other words, the fewest photons it can sense is 100, but
anything between 100 and 200 (actually 300?) will read as 0x0001. The most
that it can read before clipping is 819200 photons, but it reads that os 0x0FFF
(4095). Meanwhile a 14 bit A/D with 13bits of dynamic range would read 100
photons as 0x0002, and 819200 photons as 0x3FFF (16,383), or it would have a
resolution of 50 photos per bit of least resolution.
--
Larry Colen [email protected] sent from i4est
Uhhh...yeah....whatever.....
Rick
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