Preston Cinema Systems FI+Z Manual page 12

To select the focus ring,
to select either a ring (A – E) for metric or (Ai – Ei for imperial) (Fig. 6.23. The tables below
show the near focus distances for both the rings calibrated in imperial and metric units.
Ring Ai
Near Focus 9"
Ring A
Near Focus .25m
The printed labels Ai - Ei are pictured in Fig. 6.24 below. Note that the midpoint of each
scale is about twice the minimum focus distance. Although the ring can be chosen to
cover the entire focus range of the lens, it is often advantageous to choose the ring which
covers the minimum focus required for the actual shooting.
Fig.6.24 Increasing the "throw" of the focus knob by choosing focus ring
minimum focus.
For example the Summilux 18mm lens has an 18" near focus, matching the Bi ring.
However if the closest distance required is 3', only half of the knobs rotation would be
used. Choosing the Di ring instead would make the entire rotation of the focus knob
available and double the spread of distances, dramatically improving the precision.
Note that any focus ring can be used with any calibrated lens.
7. The Operating Mode allows the user to change which hand control axis, focus, iris, or
zoom, controls which motor. Pressing the Set-Up key (FIG. 7.1) brings up the screen
for allocating the 4-motor axes in the MDR3.
(Fig 6.22) → Ring
→Menu
Bi
18"
B
.50m
(FIG 6.21) and use the Navigation key ↕
Ci Di
24" 36"
C D
.70m 1.0m
Ei
72"
E
3.0m
12