On 9/13/2010 1:15 PM, Miserere wrote:
This is what astronomers do on ground and space-based telescopes. The issue with cameras is that the dark frame needs to be the same exposure length as the image you take; for your system to work one would take a 1/2 hour exposure (say) and the camera would figure out what the noise would be every (say) 30 secs, and would then use this data to apply a DFS for exposures henceforth. Ideally, you would be able to run a "DFS Setup" at any time and the camera would store these values in memory. It would come with default values from factory, but as the chip ages one would have to redo the setup periodically. Or if you're a stickler for detail, you'd do it at the beginning of every night you use the camera.
Right. The particular DFS frame may depend on the outside temperature. So yes, for perfect DFS, the procedure will have to be done every night. But only once for the night.
If, however, while the shutter is open, the camera would be able to save the DFS image every so many minutes or seconds, it could do it.
Or...Pentax could just make DFS optional so those who want to turn it off and do DFS with software of the computer can do so, and those who don't know what the hell DFS is (or don't care) will leave the camera on the default "DFS: ON".
I'd rather there were a bit more flexibility here. At least until they completely figure out an hour long exposure in electronics without DFS.
For what it's worth, even a camera like the Panasonic G2 has the option to turn DFS off, so there's no reason for Pentax not to implement it.
That's correct. But if Pentax want to innovate - here is the suggestion for them :-).
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