<s>
The	O
Canon	B-Algorithm
R	I-Algorithm
lens	I-Algorithm
mount	I-Algorithm
is	O
a	O
physical	O
standard	O
for	O
connecting	O
a	O
camera	O
lens	O
to	O
a	O
35mm	O
single-lens	B-Algorithm
reflex	I-Algorithm
camera	I-Algorithm
body	O
.	O
</s>
<s>
It	O
was	O
introduced	O
in	O
March	O
1959	O
along	O
with	O
the	O
Canon	B-Algorithm
Canonflex	I-Algorithm
.	O
</s>
<s>
The	O
R	O
mount	O
was	O
used	O
on	O
Canon	O
's	O
first	O
single	B-Algorithm
lens	I-Algorithm
reflex	I-Algorithm
(	O
SLR	B-Algorithm
)	O
camera	O
.	O
</s>
<s>
The	O
R	O
mount	O
was	O
discontinued	O
in	O
1964	O
and	O
replaced	O
with	O
the	O
Canon	B-Algorithm
FL	I-Algorithm
lens	I-Algorithm
mount	I-Algorithm
.	O
</s>
<s>
Many	O
mirrorless	B-Device
interchangeable-lens	I-Device
cameras	I-Device
are	O
able	O
to	O
use	O
Canon	B-Algorithm
R	I-Algorithm
lenses	O
via	O
an	O
adapter	O
.	O
</s>
