Old 20-10-2015, 08:55 AM
Camknox (Cameron)
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Join Date: May 2012
Location: Kalgoorlie, WA
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Hi folks,

I've been doing astrophotos for a bit now but I've never bothered with shooting flats, I sometimes use darks but not always. I've got myself a light box; homemade using an EL panel and some foam etc.

I've tried some sample shots and I'm not sure what I should be aiming for here. So with that in mind;

1. How long and what settings should I be exposing at? For example if my lights are 180s @ 800ISO f/0 my flats should be?

2. Is this a constant? I use APT for my image acquisition and it suggests a flat should be using the same ISO and I guess it determines the exposure time as it wont let me enter it.
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Old 20-10-2015, 09:51 AM
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Atmos (Colin)
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Location: Melbourne
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Flats should be taken at the same ISO and optical configuration but the exposure time should just be as long as it takes to bring your histogram to 50-75% of saturation.
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Old 20-10-2015, 11:14 AM
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rustigsmed (Russell)
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Location: Mornington Peninsula, Australia
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Hi cam,

Point to a blank part of the sky after sunset, turn the canon setting from manual to Av, and start snapping away. It will choose the exposure time automatically. Easy as!

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