<s>
The	O
Canon	B-Algorithm
EOS	I-Algorithm
50	I-Algorithm
(	O
also	O
known	O
as	O
the	O
ELAN	O
II	O
in	O
America	O
and	O
the	O
EOS	O
55	O
in	O
Japan	O
)	O
is	O
an	O
autofocus	O
,	O
autoexposure	O
35mm	O
SLR	B-Algorithm
camera	I-Algorithm
.	O
</s>
<s>
The	O
EOS	O
50E	O
variant	O
introduced	O
an	O
enhanced	O
version	O
of	O
the	O
3-zone	O
eye-controlled	O
autofocus	O
system	O
that	O
was	O
first	O
seen	O
on	O
the	O
EOS	B-Algorithm
5	I-Algorithm
camera	O
.	O
</s>
<s>
The	O
EOS	O
50	O
was	O
also	O
the	O
first	O
camera	O
to	O
implement	O
Canon	O
's	O
E-TTL	B-Algorithm
flash	O
system	O
.	O
</s>
<s>
E-TTL	B-Algorithm
on	O
the	O
other	O
hand	O
fires	O
a	O
low-intensity	O
pre-flash	O
before	O
exposure	O
,	O
and	O
meters	O
the	O
reflected	O
light	O
through	O
the	O
camera	O
's	O
normal	O
metering	O
system	O
.	O
</s>
<s>
Sales	O
of	O
the	O
EOS	O
50	O
began	O
in	O
September	O
1995	O
,	O
and	O
ended	O
after	O
the	O
introduction	O
of	O
the	O
replacement	O
model	O
,	O
the	O
EOS	B-Algorithm
30	I-Algorithm
in	O
October	O
2000	O
.	O
</s>
