On 9 Jan 2003 at 7:06, Herb Chong wrote: > higher ISOs are achieved mostly by increasing the analog gain of the > amplifiers. this leads to a lot of thermal noise. at least for consumer > cameras, that also means hot spots as individual pixels may go very > nonlinear. i have been thinking about writing a Photoshop filter to handle > this type of noise where you get pure R, G, or B hot spots. they can be > found because there is near no response in the other two channels at that > position.
The Oly E-20 provides for time exposures on bulb of up to 8 minutes however the results aren't too impressive if test sites are to be believed. See the following article for an interesting dissection of image noise vs ISO & exposure time: http://www.wrotniak.net/photo/e10/e10-dark.html Also the following link is to a good utility for logging hot/dead pixels in images generated with any digital camera, the test text logs can be filed for later comparison in order to determine if the response of the sensor has changed over time, see: http://www.starzen.com/imaging/deadpixeltest.htm Cheers, Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://members.ozemail.com.au/~distudio/publications.html
