STITCHING AND EXTENDING

Digital stitching software has evolved into
a widely used tool for creating images
that are larger and wider. These are actually
two separate functions. Shooting a scene with
a longer focal length in overlapping frames is
one technique for achieving higher resolution
and so larger printed images—an equivalent
of large-format photography. From the point
of view of this book, however, the interest is in
changing the shape of the final image. This tends
to be panoramic, as long horizontal images have
an enduring appeal for reasons we’ll go into
shortly, but there is also complete freedom, as the
examples here show. What is often overlooked
is the effect this stitching has on the process
of shooting, because it demands anticipation
of how the final image will look. There is no
preview at the time, and this is a situation new
to photography—that of having to imagine what
the final image and frame shape will be. It gives
stitched, extended images an unpredictability
which can be refreshing.
Panoramas have a special place in photography.
Even though proportions that exceed 2:1 seem to
be extreme, for landscapes and other scenic views,
they are actually very satisfying. To understand
why, we have to look again at the way human
vision works. We see by scanning, not by taking in
a scene in a single, frozen instant. The eye’s focus
of attention roams around the view, usually very
quickly, and the brain builds up the information.
All of the standard photographic formats—and
most painting formats, for that matter—are
areas that can be absorbed in one rapid scanning
sequence. The normal process of looking at the
picture is to take in as much as possible in one
prolonged glance, and then to return to details that
seem interesting. A panorama, however, allows the
eye to consider only a part of the image at a time,
but this is by no means a disadvantage, because it
replicates the way we look at any real scene. Apart
from adding an element of realism to the picture,
this slows down the viewing process, and, in
theory at least, prolongs the interest of exploring
the image. All of this depends, however, on the
photograph being reproduced fairly large and
viewed from sufficiently close.
This virtue of the panorama—to draw the
viewer in and present some of the image only to
the peripheral vision—is regularly exploited in
the cinema, where an elongated screen is normal.
Special projection systems, such as Cinerama
and IMAX, are premised on the realistic effect
of wrapping the image around the viewer. Still
panoramic images have a similar effect.
The frame can also be extended in postproduction
in other ways, by stretching (using
warping, distortion, and other geometric software
tools, and even by cloning). Certain images lend
themselves to being extended in one or more
directions—for instance, extending the sky
upwards, or widening the background in a studio
still-life. Magazine layouts often suggest this,
although there are ethical considerations with this
kind of manipulation, in that the final image is
not necessarily as it was seen.