<s>
The	O
Olympus	B-Algorithm
Zuiko	I-Algorithm
Digital	I-Algorithm
ED	I-Algorithm
50-200mm	I-Algorithm
F2.8-3.5	I-Algorithm
SWD	O
is	O
an	O
interchangeable	O
lens	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
announced	O
by	O
Olympus	O
Corporation	O
on	O
October	O
17	O
,	O
2007	O
.	O
</s>
<s>
It	O
added	O
an	O
ultrasonic	O
motor	O
(	O
which	O
Olympus	O
branded	O
SWD	O
,	O
for	O
Supersonic	O
Wave	O
Drive	O
)	O
to	O
the	O
existing	O
optical	O
formula	O
of	O
the	O
Olympus	B-Algorithm
Zuiko	I-Algorithm
Digital	I-Algorithm
ED	I-Algorithm
50-200mm	I-Algorithm
F2.8-3.5	I-Algorithm
introduced	O
in	O
2003	O
;	O
it	O
is	O
slightly	O
larger	O
and	O
heavier	O
than	O
the	O
earlier	O
lens	O
.	O
</s>
