Owner's Manual

ManualsBrandsCanon ManualscameraCanon EF Camera

BASIC OPERATION

F

Setting the Aperture Ring

and

the

CAT

Switch

26

The

amount

of

light

that

is

allowed

to

strike

the

film

is

determined

by

the

lens

diaphragm

.

This

amount

of

I ight

is

represented

by

"f"

numbers

or

flstops

engraved

on

the

aperture

ring

which

clicks

into

place as

it

is

rotated

.

The

f/stop

designations

indicate

the

opening

formed

by

the

diaphragm,

and

this

opening

is

called

the

aperture.

On

the

standard

50mm lens,

the

engraved

flstops

are

1.4,

2,

2.8,

4,

5.6, 8, 11,

and

16

.

At

f/l.4,

the

lens

is

at

its

maximum

aperture

with

the

diaphragm

wide

open.

For

this

reason,

f/l.4

is

said

to

be a large

flstop

even

though

it

is

small in numefical value.

And

con

-

versely,

f/16

is

the

minimum

aperture

of

the

lens

and

is

a small

f/stop

.

The

relationship

between

successive

flstops

is

arithmetic

: as

you

close

down

the

dia-

phragm, each

flstop

indicates

half as

much

light as

the

preceeding

one

. When

operating

the

aperture

ring

manually,

you

may

use

any

aperture

setting

.

For

normal AE

operation,

the

aperture

ring

must

be

set

at

the

'

A'

mark

. Hold

in

the

AE

lock pin

while

turning

the

aperture

ring

from

f/16

(or

f/22

on

some

lens.es)

to

the'

A'

mark.

At

·

this

special

setting,

the

aperture

ring

is

disengaged, allowing

the

cam~ra

to

adjust

the

lens

diaphragm

automatically

to

any

flstop

setting

. Also,

to

make

sure

that

the

camera

selects

the

proper

flstop,

the

CAT

switch

must

be

set