>> The only question hovering in my mind is the following: >> If that 22bit thingie is removing so much noise (or not introduing >> nois whatever this is not a words discussion) why wouldn't Pentax give >> access to ISO 3200 ?? Strange isn't it ? >> > > The 22bit A/D image processor does not change the noise > characteristics of the sensor. > It just occurred to me that there may be one minor improvement to the noise situation, though: I'm not 100% sure if I'm right, but the way I've understood things, the ISO setting has in the past been implemented via a variable gain stage in the analogue domain. With this oh-so-wonderful image processor, it is probably applied digitally to the 22-bit data instead. This does not do anything about the original noise or signal to noise ratio, of course, but at least it means that *additional* noise won't be introduced by the gain stage itself.
Differently put, some of what this 22-bit thingy is about, is probably that the signal is converted to digital a bit earlier in the sequence, so as to speak. This does eliminate some sources of noise - probably not the most significant ones, but still... Also, it has been suggested that the image processor will properly remove some sources of variation that aren't strictly speaking noise, like the effects minor differences in the sensitivity of the pixels. (This, type of variation may unlike actual noise, cancelled out, as it is *not* random.) - Toralf -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
