True Focus, Absolute Position Lock - Hasselblad H5D User Manual

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TRUE FOCUS AND ABSOLUTE POSITION LOCK
The obvious situation that would most benefit from using True Focus would be a fashion shoot with a fairly wide angle
lens at a large aperture setting and where the central area of the image is clothing while retaining focus on the model's
face. Ideally, a fairly controlled and static flow should be planned on (this means a change of pose by the model should take
place only after captures and the photographer must resist crouching down, or leaning forwards or backwards too much
before capture).
With the lens at its widest aperture setting, a normal autofocus setting is made on the model's face (A), and the camera
focus locked. The composition is then changed to include more of the clothing (B), but the locked focus setting now extends
beyond the model's face at (B) according to the laws of geometry. This will naturally result in an image where much of the
subject closest to the camera and the model's face will be unsharp. Solutions involving manual focus/focus lock/ resetting of
multi-point sensors are distracting to workflow and prone to error. Making a True Focus setting at (A) will ensure that focus
is automatically adjusted in accordance with the change of camera angle.
True Focus uses yaw rate technology and by way of the Absolute Position Lock (APL) processor, logs camera movement as
the basis for an extremely rapid compensatory focus reset without any shutter lag. The H5D's firmware then further perfects
the focus using the precise data retrieval system found on all HC/HCD lenses.
B A
B - ca.2.5 m
Distance when camera perpendicular ca. 2.4 m
If a True Focus setting instead of a normal autofocus setting is now made at A and
the composition changed back to B again, the camera will automatically calculate
and adjust the focus of 2.5m to approximately 2.4m, which is the actual camera to
perpendicular distance. The model's face is now sharp again.
A normal autofocus setting is made on the
A
model's face and locked.
The focus setting is approximately 2.5m.
B
When the camera is swung back down, B,
the locked focusing distance of 2.5m, ac-
cording to the laws of geometry, extends
beyond a perpendicular line drawn down
from the face, creating unsharpness.
37
A
B