to M Wa tS o n: bu i l d i nG a S c a n n i nG S y S t E M
Digital scanning backs have been in use for about ten years. They are derived
from satellite imaging systems. Because scanning backs are scientific instruments
that require a computer to run them, they have been used mainly in art galleries,
museums, libraries, universities and offset printing companies where accurate
color and precise detail are necessary to record art works and text. However, they
are becoming more popular among architectural and landscape photographers
migrating from film to digital while using the view camera they already own.
The scanning back used with the Panowide adapter motorized tripod head is
optimal for producing panoramas of various dimensions and ratios including 360°
cylindrical and spherical panoramas. Two early adopters of digital scanning backs
are Stephen Johnson and Shelley Lake. Pixel Light and Richardson Photography
also use this technology.
The Better Light scanning back is engineered to slip into the film slot of a view
camera. A view camera allows independent displacement of the lens plane and the
film plane. To be sure, using a view camera is slower and a more contemplative
way of making images, but it offers important advantages for image control.
When creating a single image, the photographer can apply front and back rise
or fall, swings, tilts and shifts to control focus, depth of field and parallel line
convergence (the Scheimpflug principle). When creating a 360° panorama, the
use of rise and fall changes the horizon line. Using tilt can change the depth of
field. For flat stitch panoramas the rear shift movement is extremely useful.^1
The look and feel of the scanning back are thoroughly professional. The insert is
a thin, torsionally rigid box within which a precision step motor turns a gear drive
that moves the Kodak trilinear sensor across the scanner opening, 72 x 96mm
in dimension. The inner workings of the electronics are best described by this
excerpt from the Better Light web site:
The trilinear sensor is mounted in a ball bearing carriage that
glides on a precision track cut into the metal body frame, and is
accurately positioned by a matched polymer nut and stainless steel
drive screw directly coupled to a high-torque step motor with up to
6400 micro-steps per revolution, for outstanding smoothness at any
motor speed. This motor is driven by a dedicated microcontroller
that also controls the sensor’s exposure and timing, for crystal-
accurate synchronization of these important functions.- For more information, see “View camera” in Wikipedia, The Luminous Landscape,
MAGNAchrom, or Using the View Camera by Steve Simmons (Amphoto Books,
1992) (see Web References, below, for URLs).