Hi Jan,
Sorry ... I haven't made myself clear. I
haven't used the 'in camera' histogram
at all. I've been talking about
Photoshop only. I haven't tried working
on that tiny screen at all.
I do shift it all to the right and that
gives excellent results. The snow has
fallen from the trees again. It will be
back in a day or two and I'll have
another go. But it looks like blown out
highlights are no longer a problem.
There will be others of course. But on
the microscope, where it really matters,
the camera is doing great. Have you
looked at the 'artsy' crystal pictures I
posted? They are TIFF files because we
need lots of pixels for printing.
Now that I've studied the RAW format a
bit I'll try that and see if there is
any advantage. I discard about 50% at
the moment. Mainly because some of the
crystals have such a short lifetime 10
~15 seconds sometimes that I have to
hurry and composition suffers. Also
magnification is available only in steps
and things often don't fit very well. I
need a Plan Apo 4X objective. They cost
several thousand dollars new. The 4X I
have -- a Leitz EF DIN -- is crappy.
Don
Jan van Wijk wrote:
Hi Don,
On Sat, 03 Dec 2005 15:00:52 +0200, Don Williams wrote:
<snip>
This is what I found. The RAW and TIFF
snow scenes were all very good without
exception. The histograms showed that
the five stops the camera is capable of
Actually, it may be close to 6 stops ...
were to be found between 1 and about
160. Spreading them using levels gave a
close match to what it actually looks
like outside.
OK, it may be better to compensate if there is
mainly white (snow) in the image, that will push
the histogram to the right, and as long as you
are not blowing any highlights 'off the edge'
there, this will give much better definitions
in the shadow areas ...
<snip>
The RAW converter is a plug-in for
Photoshop 7 that I found on the web some
time back and saved for the day I'd get
an *ist D.
AFAIK, that is just a 'plugin' version of
the Pentax RAW converter.
It works, but not that well ...
I'm working with a rather
superficial idea of what needs attention
in digital and I need a lot of practice.
In other words I don't know what the
hell I'm doing.
:-)
I could have set the
white level on snow I suppose, but left
it at automatic. I didn't want to make
too many changes at once. Oh yes ... I
noticed something else which would
confirm what you say above. The output
from the converted RAW files in
Photoshop are sharper than the TIFF
images.
That may depend on RAW converter
settings as well, but I do not know
that converter (using CS2 myself).
Also the Pentax Browser software
is better than Windows for uploading
images from the cards.
* This also reduces the very slight blue
cast. Using auto color makes them a tiny
bit too red. But the result is almost
the same and by this stage highly
subjective anyway. Manually altering the
color with the sliders can give a result
indistinguishable from the levels
dropper manipulation. In 'snow only'
pictures the camera tries to put
everything in at about 109 -- a
beautiful bell curve. I guess that's
where the *ist D thinks Neutral Gray
(18%) lies
18% gray on snow only would result in rather
'dark' snow, hence the compensation :-)
Try to get the histogram as far as possible to
the right without clipping the highlights.
The histogram shown in the RAW converter
may be more accurate than the in-camera one,
since that averages over all channels and
may not show clipping in just one channel.
Regards, JvW
------------------------------------------------------------------
Jan van Wijk; http://www.dfsee.com/gallery
--
Dr E D F Williams
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Updated: Print Gallery -- 16 11 2005
