Infrared Photography; Depth Of Field Scale; Preview Button - Olympus 1 Instructions Manual

INFRARED PHOTOGRAPHY/DEPTH OF FIELD SCALE/PREVIEW BUTTON
The OM System lenses are provided
with an infrared index mark engraved
in red on the depth of field scale to the
right of the reference dot. When shoot-
ing with infrared film, focus normally
on your subject without the red filter
on and read the subject distance on the
distance scale. Then, turn the focusing
ring to the right until the distance
reading is opposite the infrared index
mark. Your lens will then be in focus for
average infrared photography. Shoot
with the red filter on. In the above
picture the red index is set at infinity.
The double series of numbers engraved
on the depth of field scale represents F
stops: F4, F8 and F16. Once you have
focused on your subject, all objects
within the distance range indicated on
the lens distance scale between the
marks for the F stop you have selected
will have acceptable sharpness.
For example, in the above picture the
camera-to-subject distance is 3m (10ft)
and the lens is set at F16. If you read
the distance scale at the points op-
posite the engraved "16" on both sides
of the reference dot, you will find that
the depth of field is from 1.9m (6ft) to
7m (23ft). The depth of field can be
visually verified by pressing the depth
of field preview button.
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When you wish to see which objects
fall within the acceptable zone of
sharpness (depth of field), press the
preview button on your lens. The
diaphragm of the lens will stop down
to the preset F stop enabling you to
see the depth of field in the camera
viewfinder.
* If you jerk the preview button while
depressing the shutter button half-
way down, the shutter might get
released. Gently push and release the
preview button to avoid accidentally
releasing the shutter.