Re: [Openexr-devel] how to get images in EXR format?

[Florian Kainz]

Hi Andreas,

Each of the OpenEXR sample images is a combination of three
or four frames.  From frame to frame, the exposure time was
increased by a factor of four.  The lens aperture was kept 
fixed to avoid changing the depth of field.

All of the sample images were shot on negative film.  If you
are going to use a digital camera, you should try to turn off 
as much of the camera's built-in image processing as possible.  
Some digital cameras appear to perform feature-sensitive image
enhancement, which makes combining the individual frames rather 
difficult.

The dynamic range that can be captured with multiple exposures 
tends to be limited by the camera's optical system.  In the
brightest exposures, internal reflections cause fogging, and hide
details in the darkest part parts of the image.  Some of the fog 
can be removed by subtraction.  This was done on the OpenEXR 
sample images.

If you want to record images of moving objects, neither the
multiple-exposure technique nor a Panoscan camera will work;
the recording process simply takes too long.  However, you
can shoot moving scenes on motion-picture negative film, which
captures a significantly wider dynamic range than most digital
cameras; you get between 2 and 4 extra f-stops.  You can then
scan the negative to get all the recorded information, if
necessary in multiple passes, with different scanner exposure
settings.

Florian


> On Wed, 29 Jan 2003, Andreas Känner wrote:
> 
> > Hello!
> >
> > I don't know if this is the right list, but I try it anyway (forgive me
> > if this is not the right list).
> >
> > I'm currently writing a program for capturing still images. Its main
> > purpose is to capture images for stop motion animations. I wonder if I
> > should save the pictures in openEXR format, but I don't know if it
> > makes sense. Is a digital camera available, that provides images in
> > this quality? If not, is it possible to use a normal DV-Cam to produce
> > such Images? Maybe with some filters and with more than one shoot per
> > picture?
> >
> > Thank you,
> > Andreas
> >
> >
> >
> > _______________________________________________
> > Openexr-devel mailing list
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> > http://mail.nongnu.org/mailman/listinfo/openexr-devel
> >
> 
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