<s>
Zuiko	O
(	O
or	O
)	O
is	O
a	O
brand	O
of	O
optical	O
lenses	O
made	O
by	O
Olympus	O
Corporation	O
that	O
was	O
used	O
up	O
to	O
and	O
into	O
the	O
Four	B-Architecture
Thirds	I-Architecture
system	I-Architecture
era	O
.	O
</s>
<s>
With	O
the	O
introduction	O
of	O
the	O
Micro	B-Operating_System
Four	I-Operating_System
Thirds	I-Operating_System
system	I-Operating_System
in	O
2008	O
,	O
new	O
lenses	O
for	O
that	O
system	O
started	O
to	O
be	O
branded	O
as	O
M.Zuiko	O
Digital	O
.	O
</s>
<s>
The	O
engraving	O
dropped	O
the	O
number	O
of	O
elements	O
with	O
the	O
advent	O
of	O
multicoating	O
,	O
which	O
occurred	O
during	O
the	O
production	O
of	O
OM	B-Algorithm
system	I-Algorithm
lenses	O
.	O
</s>
<s>
Ace	O
,	O
Pen-F	O
,	O
FTL	O
,	O
and	O
early	O
OM	B-Algorithm
system	I-Algorithm
lenses	O
carry	O
the	O
letter	O
prefix	O
denoting	O
the	O
number	O
of	O
optical	O
elements	O
.	O
</s>
<s>
Later	O
OM	B-Algorithm
system	I-Algorithm
lenses	O
(	O
generally	O
all	O
multicoated	O
)	O
omitted	O
this	O
prefix	O
.	O
</s>
<s>
Early	O
35mm	O
fixed-lens	O
camera	O
lenses	O
Lens	O
Construction	O
Cameras	O
fitted	O
35mm	O
2.0	O
8e/6g	O
Wide-S	O
(	O
Tower	O
20	O
)	O
35mm	O
3.5	O
4e/3g	O
(	O
Tessar	O
)	O
Wide	O
,	O
Wide-E	O
(	O
Tower	O
54	O
)	O
,	O
Wide	O
II	B-Algorithm
40mm	O
3.5	O
4e/3g	O
(	O
Tessar	O
)	O
35	O
I	O
,	O
III	O
,	O
IV	O
,	O
V	O
,	O
S	O
,	O
K	O
(	O
Tower	O
56	O
)	O
42mm	O
1.8	O
7e/5g	O
(	O
Double	O
Gauss	O
)	O
35	O
S-II	O
(	O
Tower	O
18	O
)	O
42mm	O
2.0	O
?	O
</s>
<s>
In	O
1958	O
,	O
the	O
Wide	O
II	B-Algorithm
viewfinder	O
camera	O
replaced	O
the	O
Wide	O
with	O
no	O
change	O
to	O
the	O
lens	O
.	O
</s>
<s>
Olympus	O
also	O
began	O
selling	O
the	O
Olympus	O
35S	O
rangefinder	B-Algorithm
in	O
1955	O
,	O
alongside	O
the	O
Olympus	O
35Vb	O
viewfinder	O
which	O
had	O
been	O
launched	O
that	O
same	O
year	O
.	O
</s>
<s>
The	O
first	O
Olympus	O
35mm	O
rangefinder	B-Algorithm
camera	I-Algorithm
with	O
a	O
wide-angle	O
lens	O
was	O
the	O
Wide-S	O
(	O
or	O
Wide	O
Super	O
)	O
of	O
1957	O
.	O
</s>
<s>
The	O
Olympus	O
35S-II	O
replaced	O
the	O
35S	O
in	O
1957	O
using	O
a	O
body	O
similar	O
to	O
the	O
Wide-S	O
with	O
a	O
choice	O
of	O
two	O
lenses	O
,	O
a	O
faster	O
G.Zuiko	O
42mm	O
1.8	O
and	O
a	O
slower	O
E.Zuiko	O
48mm	O
2.8	O
carried	O
over	O
from	O
the	O
35S	O
.	O
</s>
<s>
The	O
35S-II	O
was	O
also	O
marketed	O
in	O
the	O
United	O
States	O
by	O
Sears	O
as	O
the	O
Tower	O
10	O
(	O
with	O
the	O
48mm	O
2.8	O
)	O
and	O
the	O
Tower	O
18	O
(	O
with	O
the	O
42mm	O
1.8	O
)	O
.	O
</s>
<s>
Olympus	O
released	O
the	O
Olympus-Auto	O
electro-set	O
(	O
1958	O
)	O
and	O
Auto-B	O
electro-set	O
(	O
1959	O
)	O
shortly	O
after	O
the	O
Ace	O
interchangeable	O
lens	O
rangefinder	B-Algorithm
,	O
using	O
styling	O
largely	O
borrowed	O
from	O
the	O
Ace	O
.	O
</s>
<s>
Both	O
of	O
the	O
Auto	O
models	O
had	O
built-in	O
exposure	O
meters	O
,	O
and	O
were	O
distinguished	O
by	O
lens	O
speed	O
;	O
the	O
older	O
Auto	O
had	O
the	O
faster	O
G.Zuiko	O
42mm	O
1.8	O
lens	O
carried	O
over	O
from	O
the	O
35S-II	O
and	O
the	O
Auto-B	O
had	O
a	O
slower	O
E.Zuiko	O
42mm	O
2.8	O
lens	O
.	O
</s>
<s>
A	O
slightly	O
faster	O
D.Zuiko	O
43mm	O
2.5	O
was	O
used	O
for	O
its	O
successor	O
,	O
the	O
Auto	O
Eye	O
II	B-Algorithm
,	O
released	O
in	O
1962	O
.	O
</s>
<s>
The	O
35LE/LC	O
were	O
followed	O
by	O
the	O
flagship	O
fixed-lens	O
35SP	O
rangefinder	B-Algorithm
of	O
1969	O
,	O
again	O
using	O
the	O
G.Zuiko	O
42mm	O
1.7	O
lens	O
.	O
</s>
<s>
The	O
35EC	O
offered	O
programmed	O
automatic	O
exposure	O
only	O
(	O
both	O
aperture	O
and	O
shutter	O
speed	O
set	O
automatically	O
by	O
the	O
meter	O
)	O
and	O
had	O
no	O
rangefinder	B-Algorithm
.	O
</s>
<s>
The	O
updated	O
35ECR	O
of	O
1972	O
added	O
a	O
rangefinder	B-Algorithm
to	O
the	O
35EC2	O
but	O
again	O
was	O
limited	O
to	O
programmed	O
autoexposure	O
.	O
</s>
<s>
In	O
1974	O
,	O
Olympus	O
released	O
the	O
35ED	O
,	O
last	O
of	O
the	O
'	O
economy	O
 '	O
line	O
,	O
equipped	O
with	O
a	O
slightly	O
wider	O
D.Zuiko	O
38mm	O
2.8	O
lens	O
,	O
rangefinder	B-Algorithm
focusing	O
,	O
and	O
programmed	O
autoexposure	O
only	O
.	O
</s>
<s>
In	O
1970	O
,	O
Olympus	O
marketed	O
the	O
35RC	O
as	O
a	O
mid-range	O
compromise	O
;	O
although	O
it	O
was	O
approximately	O
the	O
same	O
size	O
as	O
the	O
35EC	O
using	O
the	O
same	O
E.Zuiko	O
42mm	O
2.8	O
lens	O
,	O
the	O
35RC	O
added	O
more	O
advanced	O
features	O
from	O
the	O
35SP	O
including	O
true	O
rangefinder	B-Algorithm
focusing	O
and	O
the	O
option	O
of	O
either	O
shutter-priority	O
autoexposure	O
or	O
manual	O
exposure	O
control	O
.	O
</s>
<s>
The	O
35DC	O
(	O
"	O
Deluxe	O
Compact	O
"	O
)	O
of	O
1971	O
also	O
offered	O
rangefinder	B-Algorithm
focusing	O
of	O
a	O
faster	O
F.Zuiko	B-Algorithm
40mm	O
1.7	O
lens	O
,	O
but	O
was	O
limited	O
to	O
programmed	O
autoexposure	O
only	O
.	O
</s>
<s>
Finally	O
,	O
in	O
1975	O
,	O
Olympus	O
released	O
the	O
35RD	O
,	O
combining	O
the	O
faster	O
F.Zuiko	B-Algorithm
40mm	O
1.7	O
lens	O
from	O
the	O
35DC	O
with	O
the	O
shutter-priority	O
autoexposure	O
or	O
manual	O
exposure	O
controls	O
of	O
the	O
older	O
35RC	O
.	O
</s>
<s>
Also	O
in	O
1962	O
,	O
the	O
more	O
advanced	O
Pen-D	O
was	O
released	O
,	O
featuring	O
a	O
significantly	O
faster	O
F.Zuiko	B-Algorithm
32mm	O
1.9	O
lens	O
and	O
an	O
uncoupled	O
selenium	O
meter	O
,	O
whose	O
readings	O
were	O
manually	O
transferred	O
to	O
set	O
exposure	O
.	O
</s>
<s>
The	O
1965	O
Pen-D3	O
increased	O
lens	O
speed	O
again	O
,	O
using	O
a	O
F.Zuiko	B-Algorithm
32mm	O
1.7	O
,	O
and	O
a	O
Pen-D3	O
EL	O
variant	O
was	O
introduced	O
in	O
1966	O
.	O
</s>
<s>
1965	O
brought	O
the	O
PenEM	O
equipped	O
with	O
a	O
F.Zuiko	B-Algorithm
35mm	O
2.0	O
lens	O
and	O
a	O
motor	O
built	O
into	O
the	O
body	O
.	O
</s>
<s>
The	O
1967	O
PenEED	O
used	O
the	O
F.Zuiko	B-Algorithm
32mm	O
1.7	O
lens	O
from	O
the	O
Pen-D3	O
and	O
added	O
program	O
and	O
aperture-priority	O
autoexposure	O
.	O
</s>
<s>
He	O
formed	O
a	O
team	O
of	O
10	O
development	O
engineers	O
and	O
gave	O
them	O
a	O
year	O
to	O
independently	O
conceive	O
a	O
new	O
compact	O
camera	O
;	O
the	O
Konica	B-Algorithm
C35	I-Algorithm
AF	I-Algorithm
,	O
which	O
was	O
the	O
world	O
's	O
first	O
autofocus	O
camera	O
,	O
had	O
just	O
been	O
released	O
and	O
all	O
of	O
the	O
engineers	O
were	O
enthusiastic	O
about	O
designing	O
a	O
competitor	O
.	O
</s>
<s>
The	O
Zuiko	O
name	O
was	O
not	O
revived	O
until	O
2003	O
,	O
with	O
the	O
release	O
of	O
the	O
E-1	O
digital	B-Device
SLR	I-Device
and	O
its	O
line	O
of	O
'	O
Zuiko	O
Digital	O
 '	O
branded	O
four-thirds	B-Architecture
system	I-Architecture
lenses	O
.	O
</s>
<s>
Prior	O
to	O
the	O
lenses	O
built	O
for	O
the	O
Pen-F	O
half-frame	O
camera	O
,	O
Olympus	O
produced	O
the	O
Ace	O
rangefinder	B-Algorithm
camera	I-Algorithm
in	O
1958	O
.	O
</s>
<s>
Between	O
the	O
Pen-F	O
and	O
the	O
OM	B-Algorithm
system	I-Algorithm
cameras	O
,	O
Olympus	O
manufactured	O
the	O
FTL	O
camera	O
with	O
a	O
M42	B-Algorithm
lens	I-Algorithm
mount	I-Algorithm
modified	O
to	O
pass	O
aperture	O
information	O
to	O
the	O
camera	O
's	O
internal	O
meter	O
.	O
</s>
<s>
To	O
estimate	O
the	O
angle	O
of	O
view	O
of	O
Pen	B-Algorithm
half-frame	I-Algorithm
system	I-Algorithm
lenses	O
,	O
the	O
native	O
focal	O
length	O
may	O
be	O
multiplied	O
by	O
a	O
factor	O
of	O
1.4	O
to	O
obtain	O
the	O
equivalent	O
35mm	O
focal	O
length	O
.	O
</s>
<s>
Early	O
Olympus	B-Algorithm
OM	I-Algorithm
system	I-Algorithm
lenses	O
used	O
single	O
coating	O
.	O
</s>
<s>
The	O
line	O
of	O
Zuiko	O
Digital-branded	O
lenses	O
marketed	O
for	O
Four	B-Architecture
Thirds	I-Architecture
system	I-Architecture
digital	B-Device
single-lens	I-Device
reflex	I-Device
cameras	I-Device
consists	O
of	O
the	O
following	O
sets	O
from	O
least	O
to	O
most	O
expensive	O
,	O
separated	O
by	O
marketing	O
grade	O
:	O
</s>
<s>
To	O
estimate	O
the	O
angle	O
of	O
view	O
,	O
the	O
focal	O
length	O
of	O
a	O
Four	B-Architecture
Thirds	I-Architecture
lens	O
may	O
be	O
multiplied	O
by	O
2	O
to	O
obtain	O
the	O
equivalent	O
focal	O
length	O
for	O
a	O
35mm	O
camera	O
;	O
e.g.	O
,	O
the	O
9-18mm	O
zoom	O
lens	O
has	O
an	O
angle	O
of	O
view	O
equivalent	O
to	O
an	O
18-36mm	O
lens	O
for	O
a	O
35mm	O
film	O
camera	O
.	O
</s>
<s>
Likewise	O
,	O
the	O
angle	O
of	O
view	O
of	O
adapted	O
lenses	O
may	O
be	O
estimated	O
by	O
multiplying	O
the	O
native	O
focal	O
length	O
by	O
2	O
;	O
e.g.	O
,	O
a	O
50mm	O
OM	B-Algorithm
system	I-Algorithm
lens	O
adapted	O
to	O
a	O
Four	B-Architecture
Thirds	I-Architecture
camera	O
would	O
have	O
the	O
same	O
angle	O
of	O
view	O
as	O
a	O
100mm	O
lens	O
for	O
a	O
35mm	O
film	O
camera	O
.	O
</s>
<s>
The	O
line	O
of	O
M.Zuiko	O
Digital-branded	O
lenses	O
marketed	O
for	O
Micro	B-Operating_System
Four	I-Operating_System
Thirds	I-Operating_System
system	I-Operating_System
digital	O
mirrorless	B-Device
cameras	I-Device
consists	O
of	O
the	O
following	O
marketing	O
grade	O
sets	O
,	O
from	O
least	O
to	O
most	O
expensive	O
:	O
</s>
