Introduction
This accessory is intended for use
with the ground-glass focusing prism (or Critical Visual
Focuser) fitted to H16 Standard and H8 cameras. Whereas
when used alone this prism provides a horizontal image in
the front of the camera, the Eye-Level Focus enables
focusing with the ground-glass to be undetaken from the
back of the camera, in the same plane as the viewfinder
and with a vertical image. A brilliantly clear,
distortion-free image is provided, at a magnification of
10x. When the one inch lens (H16) or half-inch lens (H8)
are in use, a ratio of 1 between the image and the
subject as seen by the naked eye is obtaned; thus the
image in the Eye-Level Focus can be superimposed on the
retinic image seem by the other eye, with a consequent
increase in the instrument's brilliance and convenience
in use.
The Eye-Level Focus is particularly
recommended for focusing high-speed lenses and telephoto
lenses with the diaphragm wide open, for close-ups -
which always require very accurate focusing- and for
keeping an accurate check on depth of field.
The Eye-Level Focus [was] made
in two models: "REFSE" for H16 Standard and "REFTU" for
H8 cameras.
Instructions For Use
If your Eye-Level Focus has been
purchased separately, carry out operations A to H
below.
If your camera was supplied with
Eye-Level Focus already fitted, only operations E
to H need to be undertaken.
- Remove the tri-focal
viewfinder from the clamps at the top of the camera, and
place it in the lateral position (on lid of
camera).
- Unscrew the eyepiece lens of the
critical visual focuser, which contains the magnifier,
and which is situated in the upper front part of the
camera, and replace it by the special magnifier lens
supplied with the Eye-Level Focus.
- Unscrew the clamps which held the
trifocal viewfinder in the upper position, and replace
them by the special mountings supplied with the Eye-Level
Focus.
- Slide the Eye-Level Focus well home
onto the new mountings, so that the window in the front
part of the instrument covers the special magnifier
lens.
- Unscrew the flat-headed screw which
protects the focusing prism on the camera, as done for
normal use of the critical visual focuser.
- Without placing an objective in
front of the prism, adjust the Eye-Level Focus to
suit individual eyesight by turing the small milled knob
forwards or backwards until the grain of the ground-glass
surface of the prism is seen in sharp focus when the
camera is pointed toward the light. This adjustment
remains valid whatever the lens in use. It need only be
altered if the operator's eyesight changes.
- The instrument is now ready for use.
Place the taking lens in front of the prism, and bring
the subject into sharp focus by rotating the focusing
ring on the lens. Take care to open the diaphragm fully,
so that the brightest possible image of the subject is
obtained.
- Before filming do not forget to
return the taking lens in front of the opening in the
gate, and to set the diaphragm according to the amount of
light available and the filming speed in frames per
second.
If the image observed through
the Eye-Level Focus appears off centre or incomplete,
proceed as follows:-
- remove the metal cap A,
which is retained by two small screws;
- adjustments can now be effected in
the vertical sense by slightly turning the small screw
B, and in the horizontal sense by turning the two
screws C, in the directions shown in the sketch
above.
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