Hi Tanya,
On Sun, 7 Mar 2004 16:06:08 +1000, Tanya Mayer Photography wrote:
>And now for the onslaught of questions...
And good questions they are!
I have been dealing with most of them over the last couple of months trying
to decide on a standard workflow with the *ISTD myself ...
I'll try to answer each of them inline, probably duplication a lot of what others
already said about the subject :-)
>Can someone explain to me exactly how RAW works? I understand that it gives
>you a file that is captured exactly as you see it, without colour
>correction, compression etc. Does this also mean that the
>contrast/saturation/sharpness/noise reduction settings on the camera are
>irrelevant?
Except for the "noise reduction", yes they are irrelevant for the final image.
They are relevant somewhat because they ARE being used in creating the
two JPG images (160x120 pixels thumbnail and 3008x2008 fullsize) that are
embedded within the same RAW file (xxx.PEF)
These are used for displaying on the cameras little screen as well as for
the previewing done by most image viewers (including the Pentax one).
The "noise reduction" is still important for long exposures since that uses
a second (dark frame) exposure to take a sample of the real sensor noise.
Although other tools can reduce most of the noise afterwards, using the
"dark frame" information is simply the best way of doing it.
>In the PS CS Raw Plug-in... When I adjust the "Sharpness" and the "colour
>noise" settings it doesn't seem to make any difference to what I see on
>screen, can anybody explain this?
Either you are not applying enough of it, you are not looking at a large
enough magnification (100% is best) or you have not checked the
option to do a live "preview".
>
>How do the changes you make in the Plug In software (eg,
>saturation/contrast)differ to when you make the same adjustments within PS?
They do not differ in concept, but since they are applied in an earlier stage,
with ALL information still available, the result could be slightly better.
>
>What does the "Luminance Smoothing" control do?
That is much like blurring the image, but only as for luminance,
meaning any color information keeps the full detail available
while blurring unwanted (false) details in brightness.
Using the "Color Noise Reduction" in the same dialog does
exactly the opposite: reducing color detail while retaining
luminance detail. (useful to get rid of Moire effects)
>
>With regards to Chromatic Aberration, what does R/C and B/Y stand for -
>Red/Cyan, Blue/Yellow??
Yes, exactly.
You need either one (sometimes both) of them to reduce the color fringing
you see at high contrast edges, often stronger in the corners of the image.
(like tree branches and twigs against a clear blue sky)
>On the "callibrate" tab - are these colour controls just a different way of
>"Colour balancing" an image? What other applications do they have?
Yes, that is what they are for. Sort of a preset color correction.
As far as I understand it is mainly useful if you have multiple cameras that
might have very slight differences in color rendition, or if your camera
deviated significantly from the 'generic profile' for its type.
You could use these fields to 'correct' this builtin generic profile that the
Camera-RAW plugin has for every type of camera (like the *ISTD).
>I think I love RAW...!
So do I by now.
Under ideal, controlled lighting conditions (or when you can redo things easily)
there is not much need for RAW, since a properly exposed JPG contains nearly
all the detail obtainable from this 6 megapixel camera.
However, whenever that is NOT the case, which is most of the time for me,
the RAW format gives you much more flexibilty and 'recoverability' in
the later stages of your workflow.
Another addition to you 'bitness' questions and the many answers you got:
One big advantage of using RAW images is that it contains the actual data
coming from the CCD sensor itself, in a 12-bit precision. This means there
are 4096 hues (shades of gray :-) available to describe the brightness of
each individual pixel. In this stage each pixel is just a single color.
The other two available formats (JPG and TIFF) only have 8 bits to describe
the brightness for every pixel in a single color.
This simply means there is more information in the RAW file, that can be
used later on in the workflow. It means that you can get a lot more detail
out of shadow areas compared to JPG or TIFF even in slightly underexposed
images which is often the result of avoiding any blown-out highlights.
(That is another golden rule with digital cameras: NEVER OVEREXPOSE)
If found a really useful eBook about the subject at:
http://www.outbackphoto.com/booklets/booklets.html
I bought the "DOP2000" book (a PDF file actually :-) for 35 dollars and found
it to be the best to-the-point RAW/Photoshop-CS tutorial I have seen sofar.
The full title is: "Using Photoshop CS and RAW converters for the Digital
Photography Workflow"
Regards, JvW
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Jan van Wijk; http://www.dfsee.com/gallery
