Pentax ME Super - Open-Aperture and Stop-Down Metering Lenses

OPEN-APERTURE
AND
STOP-DOWN
METERING
LENSES
Open-aperture
SMC
Pentax
lenses
have
a
diaphragm
coupling
lever
@
on
the
back
of
the
lens
which
couples
with
the
camera
body
to
permit
open-aperture
metering.
The
ultra
telephotos
do
not
have
a
diaphragm
coupler,
so
they
must
be
used
with
the
stop-down
metering
system.
Use
of
the
Auto-Extension
Tube
Set
K
permits
open-aperture
metering.
Use
of
other
K
Series
accessories
—
standard
Extension
Tube
Set
K,
Helicoid
Extension
Tube
К,
Auto-Bellows
M
and
Bellows
Unit
Ill
requires
stop-down
metering,
Whenever
any
one
of
these
is
used
between
the
camera
body
and
ап
SMC
Pentax
lens,
the
stop-down
metering
system
must
be
used,
40e