In light of the above situation, it was decided to use a 35-mm SLR in place of a conventional viewfinder. To accomplish this, a Nikon F2 has been equipped with a Sigma 14-mm rectilinear lens and a DA-1 sports viewfinder. The diagonal field provided by this combination has a real-world value of 114 degrees, while the apparent field seen by the viewer is about 43 degrees. By modifying a Type E Nikon focusing screen so as to include a window-like mask, the real-world field of view is reduced to 56×93.5 degrees; i.e. to a field which matches that of the Gigapxl™ camera. Meanwhile, the field seen by the viewer is only 15.4×30.2 degrees; such a field being near-ideal for compositional purposes.
Use of a 35-mm camera in place of a viewfinder has several added benefits. For example, the SLR can be loaded with film having similar properties to that used in the larger camera. By shuttering both cameras simultaneously, one then obtains “preview” exposures which can be developed in advance of the 9"×18" versions; thereby providing the process lab with valuable information concerning whether or not to push or pull the latter during development. The 35-mm SLR also has proved useful for reconnoitering a site prior to bringing in the main camera. Here, the SLR provides a convenient method for framing a scene and for selecting the best vantage point.
