All modern stereo cameras are equipped with one or two zoom lenses.
The manual for the Fuji W1 states that in 3D mode its focal length varies between 7.1 mm and 26.9 mm (39–149 mm in 35 mm). The focal length of the lens has a different range of 6.3–18.9 mm (in ten discrete steps). The two ranges differ because a builtin digital zoom is used and can't be disabled.
You can see the effect of this digital zoom on the camera's monitor by pressing the button to switch back and forth between 3D and 2D modes.
The amount of digital zoom varies between 1.13x (for 6.3 mm) and 1.43x (for 18.9 mm).
The use of digital zoom not only increases noise in your images. In 3D mode it also reduces the area of the image sensor used to record an image from 10 Mpixels to 7.8 Megapixels (when zoomed out) and to 4.9 Megapixels (when zoomed in).