Terry L. Mair
Mair's Photography
158 South 580 East
Midway, Utah 84049
435-654-3607
www.mairsphotography.com
----- Original Message -----
From: "David Dyer-Bennet" <dd-b@xxxxxxxx>
To: "List for Photo/Imaging Educators - Professionals - Students"
<photoforum@xxxxxxxxxxxxxxxxxxxxxx>
Sent: Saturday, October 15, 2005 10:23 AM
Subject: Re: ExpoDisc: Overpriced gadget for suckers?
Terry <terry@xxxxxxxxxxxxxxxxxxxx> writes:
Yes I have, and I know from experience that for the best possible
result you NEED to do a custom white balance, and do it according to
the Manf. recommendations, Canon recommends using a white paper, I
also know from experience that you get better results from Canon
cameras (The only ones I own) if you use white and not an 18% gray
card as recommended by some.
Now for your test you will need to use some really off white balance
don't just use auto, which by the way does a pretty decent job, just
not as good as a custom.
In my earlier post said I believe I read it in digital photo pro, I
will have to try and find it again, this came out some months ago, I
thought every one already knew about this "problem".
I am curious though, just because they call it RAW or NEF or what ever
what would lead some one to believe that there was no real color data
contained in the file, nothing can just magically be what ever we want
it to be, if that where the case why cant we just go out and shoot
then go back to the computer and decided what speed it should have
been shot at? There has to be some information given to the
camera/computer in the first place and as you know garbage in =
garbage out.
Um, we *can* go out and just magically decide what speed it should be
shot at; that's what the "exposure" slider in ACR does, adjusts the
ISO.
So perhaps I missunderstand here, your telling me that if I shoot a shot way
under exposed at say 1/250th at what ever f stop I can go into the raw file
converter and change it after the fact, by altering the ISO setting? I dont
think so, not and get a good print.
Unless by speed you meant shutter speed, which obviously can't be
fiddled later.
The raw data is generally defined to be the actual A-to-D outputs for
each sensor site on the chip. White balance is something applied by
software in the camera after that.
And I got sidetracked on running my own tests. I was thinking of
deliberately creating a few thousand degrees Kelvin off for one
version, maybe shooting tungsten under daylight, and a custom white
balance for the second, and see how the raws compare. Maybe yet this
weekend.
--
David Dyer-Bennet, <mailto:dd-b@xxxxxxxx>, <http://www.dd-b.net/dd-b/>
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