Picture Window Pro allows extending dynamic range by using its "Stack
Images" function. In this case, extending dynamic range is but a subset
of its function. You can get a free 30 day evaluation copy of V 4.0
(very new) at <http://www.dl-c.com/Temp/> then click on the downloads
tab. Note that the older version (3.5) costs just as much as the new
since it includes a free upgrade to the new version.
The following test is from the PW Pro v3.5 manual. I haven't upgraded
yet. This may be a bit disjointed sounding since icons and images are
missing from this text.
Chuck Norcutt
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Stack Images Transformation
The Stack Image Transformation is another way to blend multiple
images. The transformation lets you blend up to five images at a
time and gives you very flexible control over how the image is
blended. You can select the relative amount of blending for each
image, use a brightness curve to vary the amount of blending, as
well as use masks. Some of the applications of this transformation
are:
• To simulate multiple exposures.
• To extend dynamic range by combining bracketed exposures
of the same scene.
• To reduce noise by combining multiple images of the same
scene.
• To combine multiple astrophotographs of the same part of the
sky to simulate a single, long exposure.
The images must be registered before stack images is used. If you
are using a digital camera, you can produce registered exposures
by using a sturdy tripod. Otherwise, you can register the images
using the Register option. See Composite Dialog (Two Images)
Stack Images Dialog
Extending Dynamic Range Example
The Stack Images transformation is ideal for combining two or
more bracketed exposures. Typically two images are sufficient —
with one image exposed for the highlights while the other is
exposed for the shadows. The images are blended via a brightness
curve. The curve is set to pass only the well exposed portions
of each image’s tonal range and block the under or over
exposed portions.
Our example is of a dresser lit by a table lamp. The exposures
were made using a digital camera mounted on a sturdy tripod.
This produced registered exposures of exactly the same size. (If
your exposures are not well registered, use the Composite transformation
to register them before stacking.)
Setting the Brightness Curve
To use the brightness curve, click . The curve display lets you control
the handling of the brightness levels. Initially, the curve is a
straight horizontal line along the top, indicating that all brightness
levels are passed through at 100%. To de-emphasize a part of the
brightness range, simply move that part of the curve down. (Shift-click
on the curve to create a control point and then drag it. The buttons to
the right of the curve set the curve shape.)
In this example, we adjusted the highlight exposure curve (right)
linearly from 0% at the shadows to 100% for the highlights. We adjusted
the shadow curve (not shown) in the opposite manner — 100% shadows to 0%
highlights. Thus the final image takes its highlights from one exposure
and shadows from the other, with a smooth transition from one to the other.
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swisspace wrote:
> Thanks fior info, I have experimented using olympus software, gimp,
> photoshop 7 and now lightroom, and raw developer, but what I am after is
> a technique to combine the outut from developing a raw image, once for
> the sky and the other for the shadow detail and just add then together,
> without paying for CS. you are right though, I am just trying to cheat
> and should put more time and effort into it.
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