Pentax Program Plus Program Plus Manual - Page 47

The

shutter

-speed

and

aperture

combination

in

the

Programmed

AE

mode

is

shown

in

the

chart.

The

red

line

represents

the

variation

of

shutter

-

speed

and

aperture

combination

with

an

f/1.4

lens.

Note

that

only

the

shutter

-speed

slows

down

after

the

lens

aperture

reaches

its

limit

of

f/1.4

in

combination

with

a

speed

of

approx.

1/30

sec.

When

you

use

a

lens

with

a

different

maximum

aperture,

the

exposure

program

varies

the

aperture

and

the

shutter

-speed

in

combination

until

reaching

the

maximum

aperture

of

your

lens.

For

example,

with

an

f/2.8

lens

the

program

varies

the

combination

as

shown

by

the

red

dotted

line.

Note

that

only

the

shutter

-speed

changes

after

the

maximum

aperture

is

reached.

The

fine

red

line

in

the

Programmed

AE

diagram

indicates

the

Automatic

Exposure

control

range

for

a

lens

with

minimum

aperture

smaller

than

f/22,

or

for

a

film

with

ISO

speed

other

than

100.

The

fine

red

-dotted

line

indicates

the

range

for

a

lens

with

maximum

aperture

smaller

than

f/1.4,

or

for

a

film

with

ISO

speed

other

than

100.

Meter

coupling

range

and

Shutter/Aperture

coupling

range

The

meter

coupling

range

means

the

range

of

subject

luminance

within

which

the

built-in

exposure

-meter

works

to

control

exposure.

The

shutter/aperture

coupling

range

is

that

part

of

the

meter

coupling

range

within

which

shutter

-speed

and

aperture

value

can

be

combined

for

proper

exposure

control.

When

you

use

a

50mm

f/1.4

normal

lens

and

an

ISO

100

film,

the

meter

coupling

range

is

from

EV

1

(f/1.4-1

sec.

or

f/2.2

sec.)

to

EV

18

(f/16-1/1000

sec.

or

f/22-1/500

sec.).

The

range

varies

according

to

film

speed

(ISO).

The

variation

of

the

meter

coupling

range

is

shown

by

slanting

lines

which

shift

with

ISO

ratings.

The

frame

in

the

center

shows

the

meter

and

shutter/aperture

control

coupling

range.

EV

(Exposure

Value)

EV

represents

a

combination

of

the

shutter

-speed

and

the

lens

aperture

which

is

determined

by

the

film

speed

(ISO)

and

the

brightness

of

the

subject.

43

•

Pentax Program Plus Program Plus Manual - Page 47

Shutter/Aperture

Page 47 highlights