Re: [Leica] Panorama question

[Henning Wulff <henningw@archiphoto.com>]

At 10:51 AM -0500 11/14/01, Zeissler, Mitch wrote:
>All...
>
>In scanning images from my Voigtländer 21mm lens while on vacation, I
>noticed that there is significant distortion in the outer portions of
>the image frame.  This is not an issue with stand alone images, but it
>is a major problem for me when I attempt to create panoramas with Adobe
>Photoshop Elements.  Also, Elements cannot handle the 90MB files I am
>working using without crashing [I have 512MB of RAM, so that shouldn't
>be the issue].
>
>My questions are thus:
>
>1)  What other *good* stitching programs are others using with success?
>And...
>2)  What new Leica wide-angles have the least amount of distortion?
>
>Thanks in advance.
>
>/Mitch Zeissler
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Regarding 2):

The 21 CV has very little distortion; in fact, it has somewhat less 
than the current 21 ASPH from Leica. This is using the term 
'distortion' to refer to the usual criteria of constant image 
magnification, meaning that the lens images straight lines in the 
subject as straight lines on film. You're not going to get any 
significant improvement by going to any other lens.

'Perspective distortion', or the distortion seen in the corners of 
very wide angle images due to the very lack of geometric, linear 
distortion mentioned above, is unavoidable if some form of geometric 
distortion isn't accepted. Fisheye lenses have less distortion in 
some ways, and rotating lens cameras create images with a certain 
amount of geometric distortion which reduce other types of 
distortion. If you want very wide, you have to make compromises.

With regard to stitching, use only the middle of very wide angle 
lenses. If you want your final image to subtend a very large angle 
vertically, use your 21 vertically (portrait) and overlap your images 
so that you only need to use about 1/3 or less of each frame. Then 
your 'distortion' problems will start to go away. The thinner the 
slice, the less the 'distortion'.

With respect to your program; if Adobe Elements is like Photoshop, 
512Mb is not that much for handling 90Mb image files. What with the 
undo files, and intermediate states the amount of data being shuffled 
can be a lot more.

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    *            Henning J. Wulff
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