How Lenses Tilt with Images
It’s all but a given that we use a camera to photograph something straight in front of us. But sometimes it’s better
if we cheat a bit. For that cheating, we use a lens that shifts what the camera is focused on over to the side. Or it
can tilt its focus to make objects near and far part of the same sharp image. Not surprisingly, the lens is called a
tilt-and-shiftlens. At one time, just about all lenses were tilt-and-shift. The bellows you find on ancient view
cameraslent themselves perfectly to a lens that could turn and sway. Today’s tilt-and-shift lenses are
expensive, used primarily by architectural photographers who need to keep the horizontal and verti-
cal lines of a building on the beam. And strangely, to have descended from an instrument so wed-
ded to precision, there is the tilt-and-shift’s black sheep nephew, the Lensbaby, which uses the
same laws of optics found in the older lens to introduce intentional distortion and blur.
(^130) PART 2 HOW DIGITAL CAMERAS CAPTURE IMAGES
When taking a photo of a tall building, most photographers do one
of two things. The first is to angle the camera up so it captures the
entire building. Because the focal plane is no longer parallel to the
side of the building, this approach produces a perspective that may
work for some photos but not for others.
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The other method is for the photographer to move back far
enough so that the entire building is included in the frame while
the camera remains level. This keeps the lines of the building
parallel. But it’s not always possible to get far
enough away to have a clear shot of a tall
building, and even
when it’s possi-
ble, this method
winds up with
streets and park-
ing lots taking
up half the
frame. The pho-
tographer is throwing
away half the camera’s pixels.
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The front elements of a tilt-and-shift lens
move—shift—vertically and horizontally.
Seemingly minuscule movements produce
jumbo changes in the photograph.
Shifting the lens a couple of millimeters
gets the same results as if the photogra-
pher had climbed a 20-foot ladder.
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