Pentax SF1 Manual page 39

FI Signal
[►] = Front-focus signal: Turn the focusing
ring to right,
[ = Back-focus signal: Turn the focusing
ring to left.
I o] - In-focus signal: The subject is in
focus.
►
^ = Out-of focus-range warning: Unable
to focus.
Only lenses with a maximum aperture of f/5.6 or larger
can be used in the FI system. The FI signals may appear
in the viewfinder even when some other slower lens
(such as 1000mm f/8) is mounted for high-contrast
subjects, but the accuracy is not at the optimum level.
For such lenses, use the matte area of the viewfinder
for focusing,
* SMC Pentax Bellows 100mm f/4, SMC Pentax Shift
28mm f/3.5 (when shifted) and reflex-type lenses cannot
be used in the FI system. Use the matte area of the
viewfinder for focusing.
Focusing Using the Viewfinder Matte Area
For subjects that are difficult to focus on automatically
or measure the distance to, and when using an old
Takumar-series lens with the Mount Adapter K (optional),
use the matte area of the viewfinder for manual focusing.
• Set the focus-mode switch at the MANUAL position.
• Turn the lens focusing ring to the point where the
subject appears most clearly, then release the shutter.
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