Ricoh PENTAX K-3 Mark III Faq page 50

With the automatic exposure control, the camera operate as follows.
Memo:
-[F---] apertures for the aperture indicator on the status screen, etc. When [Aperture Info
displayed, and only "F" blinks.
Caution:
-When shooting using the automatic exposure control, note the following points.
-Images can be taken with the set aperture value but an exposure deviation may occur.
- When shooting with the optical viewfinder, you cannot check the shutter speed and
ISO sensitivity before shooting because the metering is performed immediately before
the shutter is released. When shooting with Live View, you can check the shutter speed
and ISO sensitivity before shooting because the aperture is always narrowed down.
-When a lens with automatic diaphragm is attached, the aperture is narrowed down
immediately before the shutter is released, causing a time lag in the shutter release.
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