On 17/9/06, Lawrence Kwan, discombobulated, unleashed: >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.
AFAIK there is a native natural sensitivity at which a sensor is based on. Everything else is an electronic process to either lose sensitivity (slower) or increase sensitivity (faster). On a TV camera, this is more harshly labelled as 'gain' (which is exactly what it is), and used only to increase sensitivity - but the noise soon mounts to what would usually be unacceptable, although in a case of filming police at night arresting violent offenders (say) the pictures override the loss in quality. The natural sensitivity of the sensor seems a lot higher on these cameras. To 'slow' things down, there is a filter wheel in the camera body just behind the lens/in front of the sensor with 3 varying ND levels and 1 clear. So you could say that with any camera sensor there is one actual ISO, and all the rest are 'fake'. -- Cheers, Cotty ___/\__ || (O) | People, Places, Pastiche ||=====| http://www.cottysnaps.com _____________________________ -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
