Basic Explanation Of Tilt - Hasselblad HTS 1.5 Manual

With a basic understanding of the principles behind
tilt and shift, you will gain more confident control of
the HTS 1.5 and be able to exploit its potential to the
optimum.
The function of a camera lens is to project an image onto a sen-
sor. The sensor, being effectively two dimensional and lying in a
specific plane, can only record a two dimensional flat plane, in
the same orientation, in the subject.
In practice we normally perceive some areas in front and behind
this flat plane in the subject as "sharp" and this is termed the
depth of field (which in its turn expands or contracts according
to aperture setting and subject distance).
Original scene
from camera
viewpoint

Basic explanation of tilt

Tilt
Subject plane
Depth of field
Tilt
The lens is normally set perpendicular to the image plane and
therefore is effectively in parallel with the sensor as well. This
provides three planes to consider – the sensor, the lens and the
subject – all parallel. They are also interrelated, so moving one
will have an effect on the others. This is where tilt is introduced.
In the diagram below, the image plane, lens plane and subject
plane are parallel. This creates an area of acceptable sharp-
ness – the depth of field. In this case, not all of the subject
lies within the boundaries of the depth of field and those parts
therefore appear unsharp. By tilting the lens it is possible to
include more of the objects in the depth of field without having
to use a smaller aperture.
Image (sensor) plane
Lens plane
4
In this case, the lens is
focused in front of the
yellow object.
At the given aperture
setting, the yellow object
is covered by the depth
of field, the red object
partly covered and the
blue object not covered
at all. The yellow object
will therefore be accept-
ably sharp, the red object
partly sharp and the blue
object unsharp.