Adjustment Of Flange Focal Length - FujiFilm FUJINON Premista28-100mmT2.9 F/M Mode D'emploi

５. ADJUSTMENT OF FLANGE FOCAL LENGTH
The flange focal length is the distance from the flange (mounting surface) of a lens to the focal plane.
If the focal plane of the lens does not coincide with the image plane of the camera, the object will be out of focus
during a zoom operation. To prevent this from happening, the adjustment of the flange focal length is required.
Make sure to carry out the adjustment when installing
the lens to a camera for the first time or installing it to
another camera.
5.1 CONDITIONS OF OBJECT AND APERTURE
. Object : Use the Siemens Star (the chart made
up of radial black and white lines) at
the end of this manual as an object.
. Distance of object
: About  meters
. Aperture : Open or as near to open as possible.
Note: The depth of field decreases by opening the aperture of the lens, and it becomes possible to focus on an
object more precisely. To precisely adjust the flange focal length, carefully adjust the focus as much as
possible.
5.2 ADJUSTMENT
After installing the lens to the camera and turning it ON, perform adjustment by watching the monitor of the
camera.
a. Loosen the F.f adjustment ring locking screw by rotating it counterclockwise.
b. Operate the zoom to set it to the wide end.
c. Rotate the F.f adjustment ring using the F.f adjustment ring locking screw to focus on the Siemens Star
located approximately  meters away. The position where the radial black and white lines become sharpest
is the optimum focus position.
d. Operate the zoom to set it to the telephoto end.
e. Operate the focus to bring the object into focus.
f. Operate the zoom to set it to the wide end again, and check that the optimum focus position adjusted in
step 'c' is kept.
g. To adjust precisely, repeat the above steps 'b' through 'f' several times.
(If the most optimum focus position usually holds in all zoom areas, the flange focal length is adjusted
precisely. If it is not focused, the flange focal length is not adjusted sufficiently.
In this case, start adjusting again from step 'b.' )
h. Finally tighten the F.f adjustment ring locking screw firmly.
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Flange
Focal Plane
Flange Focal Length
F.f ADJUSTMENT RING
F.f ADJUSTMENT RING
LOCKING SCREW