On 17/09/06, Lawrence Kwan <[EMAIL PROTECTED]> wrote: > On Sat, 16 Sep 2006, Jens Bladt wrote:
> But isn't it true that ISO 3200 in some cameras is just ISO 1600 pushed to > simulate ISO 3200? Not sure about *istD*, but apparently many Canon's > were like this from reading at dpreview (they called it fake 3200). The > fact that you need to "override" to get to 3200 certainly indicates > that this may be the case. > > If this is true, then it should be no different simulating it yourself. > I.e. shoot with Exposure Compensation set at "-1", and then increase the > exposure by one stop at RAW post processing. Every effective ISO apart from the ISO which corresponds with the sensors natural sensitivity is an electronic simulation. Look at it this way, the sensor its self can't be made to be more or less sensitive because the well sensor well size is fixed and each has a finite capacity. Dependent upon the cameras system there may be pre-amplification of the signal before the ADC and this may effect the noise factors in some systems (not the K10D). I assume that the reason people often cite differences between images shot at ISO3200 and ISO1600 -1 stop compensation is likely due to the way that the gamma curves are applied based on the selected ISO. -- Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://home.swiftdsl.com.au/~distudio//publications/ Pentax user since 1986, PDMLer since 1998 -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
