<s>
The	O
Olympus	B-Algorithm
E-1	I-Algorithm
,	O
introduced	O
in	O
2003	O
,	O
was	O
the	O
first	O
DSLR	B-Device
system	B-Algorithm
camera	I-Algorithm
designed	O
from	O
the	O
ground	O
up	O
for	O
digital	B-Application
photography	I-Application
This	O
contrasts	O
with	O
its	O
contemporaries	O
which	O
offered	O
systems	O
based	O
on	O
reused	O
parts	O
from	O
previous	O
135	O
film	O
systems	O
,	O
modified	O
to	O
fit	O
with	O
a	O
sensor	O
size	O
of	O
APS-C	B-Algorithm
.	O
</s>
<s>
The	O
E-1	O
uses	O
the	O
Four	B-Architecture
Thirds	I-Architecture
System	I-Architecture
lens	B-Algorithm
mount	I-Algorithm
and	O
imaging	O
system	O
.	O
</s>
<s>
This	O
design	O
choice	O
means	O
that	O
because	O
the	O
CCD	B-Algorithm
is	O
smaller	O
than	O
a	O
35mm	O
negative	O
,	O
Four	B-Architecture
Thirds	I-Architecture
System	I-Architecture
lenses	O
and	O
camera	O
bodies	O
can	O
be	O
made	O
smaller	O
and	O
lighter	O
than	O
those	O
of	O
preceding	O
SLRs	O
.	O
</s>
<s>
By	O
turning	O
on	O
the	O
"	O
Noise	O
Removal	O
"	O
(	O
not	O
"	O
Noise	O
Filter	O
"	O
)	O
,	O
the	O
E-1	O
will	O
do	O
a	O
“	O
dark	B-Algorithm
frame	I-Algorithm
subtraction	I-Algorithm
”	O
to	O
get	O
rid	O
of	O
these	O
erroneous	O
bright	O
spots	O
.	O
</s>
<s>
The	O
development	O
of	O
the	O
E-1	O
involved	O
the	O
revitalization	O
of	O
Olympus	O
 '	O
old	O
Zuiko	O
lens	O
brand	O
,	O
through	O
a	O
new	O
range	O
named	O
"	O
Zuiko	O
Digital	O
"	O
with	O
the	O
Four	B-Architecture
Thirds	I-Architecture
system	I-Architecture
lens	B-Algorithm
mount	I-Algorithm
.	O
</s>
<s>
Olympus	O
initially	O
gave	O
away	O
free	O
adapters	O
to	O
connect	O
OM	O
lenses	O
to	O
the	O
new	O
Four	B-Architecture
Thirds	I-Architecture
System	I-Architecture
mount	O
.	O
</s>
<s>
This	O
adapter	O
allowed	O
a	O
wide	O
range	O
of	O
OM	O
lenses	O
to	O
be	O
used	O
with	O
the	O
new	O
Olympus	O
DSLRs	B-Device
.	O
</s>
