Polaroid Joshua Vision Service Manual page 21

As shown in Figure 1-14, a second mirror — the taking mirror — is mounted on the underside of the fresnel
screen. When the shutter button is fully depressed, the pivoted fresnel screen/taking mirror assembly is
unlatched and driven upward into the optical path to the 45-degree angle position shown. A fraction of a
second earlier, a blind was moved into place within the viewfinder window to prevent stray light from
reaching the film.
If the subject is 2.7 m (9 ft.) or more from the Camera (determined automatically from strobe wink
reflectance data), an internal far focus lens is automatically rotated into the optical path, for proper focusing.
Film exposure occurs as the shutter blades are opened and closed. Then the taking mirror is driven back
down to its original position and the viewfinder blind is opened.
Figure 1-14. Movement of Taking Mirror into Optical Path during Exposure
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