Adjusting the Flange
If the lens does not stay in focus properly as you
zoom from telephoto to wide angle, adjust the
flange focal length (the distance from the plane of
the lens mounting flange to the imaging plane).
Make this adjustment after mounting or changing
The position of the controls for adjusting the flange
focal length vary somewhat from lens to lens. Check
the identification of the various controls in the lens
Set the iris to manual.
Open the iris. Place the flange focal
length adjustment chart about 3 m (10
ft) away from the camera, lit well
enough to provide a satisfactory video
Loosen the fixing screws on the F.f or
F.B ring (flange focal length adjustment
Use manual or power zoom to set the
lens to telephoto.
Point the camera at the chart by turning
the focus ring and focus on it.
Set the zoom ring to wide angle.
Turn the F.f or F.B ring until the chart
is in focus, being careful not to disturb
the focus ring.
Adjusting the Flange Focal Length
About 3 m (10 ft)
Repeat steps 4 to 7 until the chart stays
in focus all the way from wide angle to
Tighten the F.f or F.B ring fixing