Difficult technical question on ISO & light

Chris Brown wrote:

In article ,
Tom Phillips wrote:

Film can be exposed for hours. Try that with a digital sensor.
It simply one of the differences between these two imaging
mediums.


You really should avoid such pontifications unless you're absolutely certain
you're correct, as you aren't in this case. Canon's current DSLRs, to take
one example, manage perfectly hapilly with multi-hour exposures. The only
major problem is that holding the shutter open that long may drain the
battery.

The EOS 1v has a clever shutter mechanism that holds the shutter open with
virtually no battery drain. I don't know if they've incorporated this into to
the 10D/20D or into the higher end cameras.

You can always use a grip with AA or rechargeable batteries in it for long
exposures.

Cheers,
Alan

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Tom Phillips wrote:

The ability of the canon EOS to do astrophotography is
in part due to the employment of a larger pixel. Larger
pixels mean a better signal and less noise, *but* (also

Further, CMOS (Canon) is less prone to heating over long exposures than CCD
based cameras.



--
-- rec.photo.equipment.35mm user resource:
-- http://www.aliasimages.com/rpe35mmur.htm
-- e-meil: there's no such thing as a FreeLunch.--