Re: too much light

Gladiator <no@xxxxxxxxxxxxx> wrote in
news:28b3a3h66f5bor44f580ivm4gopb3dk2jq@xxxxxxx:

On Fri, 20 Jul 2007 19:57:52 -0700, Desert Dweller
<1@xxxxxxxxxxxxxxxx> wrote:

Is moonlight also "good lighting?"

Yea, even complete darkness is good if you do a long enough exposure.
It's never truly dark out there. Digital cameras don't handle dark
very well though, at least mine doesn't. Get lots of noise when I try
night photography on it.

There is noise in a long exposure that is the same in successive frames.
You need to either take a black frame yourself, with the same "exposure
time" as the actual exposure, and subtract it (or a stack of blackframes
if you're working with a stack of images), or enable the camera's built-
in long exposure noise reduction, if it has that option.

If you need to do it yourself, it's best done in RAW first, but still
worthwhile with conversions.

--

<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <JPS@xxxxxxx>
<<> <>>< <>>< ><<> <>>< ><<> ><<> <>><
.

Relevant Pages

  • Re: CMOS vs. CCD -- Link to Article
    ... since the reason the Canon cameras ... >>data on the rate the noise grows with time for each pixel, ... There is a dark ... > a long exposure, measure the noise, and square that value. ...
    (sci.astro.amateur)
  • Re: In-camera noise FILTERING is a disaster, in most cases
    ... NR is "dark frame subtraction" and is used when exposure ... There is no heat build up for a long exposures, the noise is from dark ...
    (rec.photo.digital.slr-systems)
  • Re: CMOS vs. CCD -- Link to Article
    ... >data on the rate the noise grows with time for each pixel, ... >will perform an automatic dark subtraction), ... >'dark' from these numbers, and subtract it. ... a long exposure, measure the noise, and square that value. ...
    (sci.astro.amateur)
  • Re: Deep Sky Imager II Noise Reduction
    ... exposure taken at a certain temperature to a "dark" exposure taken at ... This ensures noise is minimized. ... chip in the DSI II has lower dark current noise than a DSI I chip. ...
    (sci.astro.amateur)
  • Re: NOT scanning negatives as positives
    ... The average noise equals the square root of exposure level. ... increases -- but not as much, so that effectively, if you vary the exposure *of the CCD*, the signal-to-noise ratio improves. ... lower CCD exposure levels, but those levels cannot be increased indefinitely by longer integration/exposure times because that would cause clipping of the most transparent film areas. ...
    (comp.periphs.scanners)