Re: using digital camera

> Why do you suppose that is?
>
> Pam
>
> Michael Keller wrote:
> >
> > I've used a zone plate on a Nikon D1. Not real thrilled with my results,
> but
> > I think it's just me. With digital, long exposures can lead to increased
> > noise in the shadows.

The CCD chips tend to give a signal not only when they are exposed to light
but also to temperature. This leads to ´thermal noise´, that can be seen best
in the dark parts of the image and that accumulates over time.

Astronomers, who have kind of an addiction to long time exposures of dark
skies, cool down their CCD cameras to minimize that noise.

servus

martin adler

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