Praktina FX - img010

24 pages

To Next Page

To Next Page

To Previous Page

To Previous Page

Loading...

Example

.1:

Des

'

ired

'

depth

of

fiel'd

3-15

m

Example

2:

Desired

depth

of

field

1-2

m,

Diaphragm

stop

re'luired:

f/16

Judging the depth

of

field

is

made

possible

by

the

two

depth

of

field

scales,

complementing

one

another,

on

the

lens

mount.

One

of

these

i,s

rotatable

with

the

focusing

ring

of

the

lens

and

is

engraved

with

a di.&tance scale.

The

other

scale

is

rigid,

with

d<iaphra'gm

num-

bers

engraved

on

the

left

and

right

of

the

rc

·d

triangle_

Try

it

out

y~urself,

looking

for

a dia-

p,

hragm

stop

relative

to

a

depth

of

fidd

covering

the

distance

between

3

meters

and

approx.

15 me.'

ters.

You

turn

the

di&t

.

ance

ring

of

the

lens

until

the

two

numbers

3

aud

15

meet

the

same

dia-

p,

hrasm

numher

on

the

right

and

the

left.

In

our

example

(Tessar

f/2.

a,

focal

length

5 cm)

this

would

mean

the

diaphragm

stop

f/S,

covering

a .

range

between

2.S

meters

and

15 m,eters,

whereby

-

speaking

inci.dentally

of

the

Praktina

FX

-

th

·e

distance

shown

hy

the

red

mark

is

approx

,

5

meters.

Focusing

is

·

thus

performed

automati-

cally.

6