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Old 12-01-2007, 12:38 PM
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dcnicholls
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Location: Canberra, Oz.
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Quote:
Originally Posted by erick View Post
Thanks DN.

I'll go with the exposure meter reading and bracket around that.

I won't be tracking, but I would have thought I could go up to 15 sec without trailing with the 55mm lens, probably less than 10 seconds for the 135mm lens. But I'm not anticipating having to expose for more than a few seconds??
You could be right. It depends on how far north or south the comet is, and thus its movement per second. The way did it last time was to work out the grain size of the emulsion (using Ilford HPS and Kodak Tri-X) and worked out how long the trail would take to traverse one grain. However, with slide film, that's not so easy.

DN
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