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Old 25-04-2009, 07:43 AM
cfranks (Charles)
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Half-Well capacity

Hi,

I have a Hutech modded 40D and am trying to build a light box for the taking of Flats. I believe the Flats have to be at half-well capacity to give proper results but I can't find what value to look for (and even where to find it).
Any help would be appreciated.

Charles
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Old 25-04-2009, 08:54 AM
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RB (Andrew)
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When I take flats with my 20Da, I use the histogram as a guide instead of well capacity calculations.
I try to have the spike at around 1/3rd the way along the histogram.
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Old 27-04-2009, 09:10 PM
cfranks (Charles)
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Thanks RB, I'll give that a try. 1/3rd from the left or right of the Histogram?
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Old 28-04-2009, 09:21 AM
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RB (Andrew)
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Yep, approximately a third from the left (on the camera's LCD) .
I'll see if I can dig up an old one when I get the chance and post what my histogram looks like in Photoshop for you.
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Old 28-04-2009, 09:57 AM
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OK here's one with the histogram.

Attached Thumbnails
Click for full-size image (My-Flat.jpg)
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Old 30-04-2009, 07:13 AM
cfranks (Charles)
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That's great. My first attempts (before this thread) were way too bright. Now I have to work on getting a uniform brightness across the light box. Many thanks.
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