Quote:
Originally Posted by Phiber
Ian, i'd be interested in comparing pics taken by both modded and normal 40D, would you have a link for that ?
Tandum, i'm not an expert at all, but i think when imaging in narrowband, you'll always end up multiplying the exposure time quite a lot (i heard between 2 to 3 times depending on the filter used)
--> Correct me if i'm wrong
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That will be because you are dealing with very small numbers of photons when using narrow band filters compared with broadband or bandpass or band stop filters , and assuming the transmission of light in the permitted band is near 100%.
The sensitivity of the detector in the pass band is also important and needs to be compensated for , is 1/2 the light ==> 2x the exposure or one less lens stop (ie f/2.8 becomes f/2 etc)