<s>
The	O
EF	O
200	O
–	O
400	O
mm	O
4L	O
IS	O
USM	O
Extender	O
1.4	O
×	O
is	O
an	O
EF	B-Application
mount	I-Application
super	O
telephoto	O
zoom	O
lens	O
produced	O
by	O
Canon	O
.	O
</s>
<s>
It	O
is	O
part	O
of	O
the	O
professional	O
L-series	O
and	O
functions	O
with	O
the	O
Canon	B-Algorithm
EOS	I-Algorithm
line	O
of	O
cameras	O
.	O
</s>
<s>
It	O
is	O
the	O
first	O
and	O
only	O
EF	B-Application
lens	I-Application
with	O
a	O
built-in	O
extender	O
.	O
</s>
<s>
Although	O
not	O
the	O
first	O
lens	O
to	O
be	O
equipped	O
with	O
a	O
built-in	O
teleconverter	O
,	O
an	O
honor	O
that	O
belongs	O
to	O
the	O
older	O
Canon	O
FD	O
mount	O
1200mm	O
5.6L	O
1.4	O
×	O
lens	O
,	O
the	O
EF	O
200	O
–	O
400	O
is	O
the	O
first	O
to	O
be	O
for	O
the	O
EF	B-Application
mount	I-Application
,	O
and	O
the	O
first	O
to	O
enter	O
mass	O
production	O
.	O
</s>
<s>
The	O
extender	O
,	O
when	O
engaged	O
,	O
increases	O
the	O
lens	O
 '	O
focal	O
length	O
by	O
a	O
factor	O
of	O
1.4	O
×	O
,	O
while	O
decreasing	O
the	O
aperture	B-General_Concept
by	O
a	O
single	O
stop	O
,	O
changing	O
the	O
lens	O
to	O
a	O
280	O
–	O
560mm	O
f/5.6	O
lens	O
.	O
</s>
