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[Rollei] Re: Rollei panorama head

Richard Knoppow wrote:

> One problem I've found with shooting panoramas with the
> Rollei head or just in general with multiple images from a
> standard camera is the mismatch at the edges of the pictures
> due to the "distortion" from the rectilinear geometry of the
> lens.
> If you photograph an array of spherical objects, say golf
> balls, you will find those at the corners of the picture are
> egg shaped. If the picture is viewed from the correct
> distance with one eye, the golf balls will look round again.
> This is because of the diminishing perspective when viewing.
> This is also the cause of the "distortion" when using wide
> angle lenses. It really isn't distortion, it comes from
> viewing from the wrong distance. If an array of circles on a
> flat surface is photogrphed they will be reproduced as
> circles since in both life and when viewing the photo the
> perspective will make them appear somewhat eliptical. This
> is why the "distortion" does not have any effect when
> enlarging or projecting.
> The effect when combining photos for a panorama is to
> distort the shape and angles of intersection at the edges.
> The effect could be eliminated by projecting onto paper held
> on a spherical surface or by using a special corrector lens
> giving the same effect. This correction is easily done using
> a computer but not easy for photographic printing.
> I am _very_ suspicious that the beautiful examples of
> panoramic photos shown in the Rollei instruction manual were
> actually photographed with a rotating panoramic camera, they
> match too perfectly.
> The mismatch can be seen in Carlos's photo but is not too
> obvious because of the subject matter and also the
> outstanding job of matching the tonal rendition of the
> sections. It can, however, be seen in the railing.
> As for the use with a 75mm vs: an 80mm lens, the 75mm
> might be better because of larger overlap but it may also be
> that the panoram head turns closer to the rear nodal point
> of the shorter lens. I suspect error from any mis-match here
> is very slight, if it exists at all.
> Note, that since the lens moves with regard to the swivel
> point of the adaptor when the distance of focus is changed
> that the match with the nodal point will not be as good for
> close objects as for distant ones. Also, the overlap will be
> less since the effective viewing angle of the lens is less
> with close objects (except for front element focussing
> lenses or when a close up diopter attachment is used).
> This is a remarkably good example of a panoram photo.

Up-top you are describing so-called "projection distortion." I do not print
for seemless panoramas but instead frame with slim boarders between images
or frame individually. Artistically, I prefer this to attempts at "seemless"
panoramas, computer manipulated or other-wise...

Re: 75 vs 80, like you I think the nodal point may be closer with the
shorter lenses... that has been my experience but wondering if Rollei had
anything to say about this?

Eric Goldstein