<s>
The	O
Leica	B-Algorithm
R	I-Algorithm
bayonet	I-Algorithm
mount	B-Algorithm
is	O
a	O
camera	O
lens	B-Algorithm
mount	I-Algorithm
system	O
introduced	O
by	O
Leitz	O
in	O
1964	O
.	O
</s>
<s>
The	O
R	O
mount	B-Algorithm
is	O
the	O
standard	O
method	O
of	O
connecting	O
a	O
lens	O
to	O
the	O
Leica	B-Algorithm
R	I-Algorithm
series	O
of	O
35	O
mm	O
single-lens	B-Algorithm
reflex	I-Algorithm
cameras	I-Algorithm
.	O
</s>
<s>
The	O
mount	B-Algorithm
is	O
descended	O
from	O
those	O
used	O
for	O
the	O
Leicaflex	B-Algorithm
,	O
Leicaflex	B-Algorithm
SL	I-Algorithm
and	O
Leicaflex	B-Algorithm
SL2	I-Algorithm
SLR	B-Algorithm
cameras	I-Algorithm
,	O
but	O
differs	O
in	O
the	O
cams	O
used	O
to	O
communicate	O
lens	O
aperture	O
information	O
to	O
the	O
camera	O
.	O
</s>
<s>
3	O
cam	O
lenses	O
are	O
compatible	O
with	O
all	O
of	O
the	O
Leica	O
SLR	B-Algorithm
cameras	I-Algorithm
,	O
while	O
R-only	O
lenses	O
have	O
a	O
slightly	O
different	O
mount	B-Algorithm
shape	O
that	O
will	O
not	O
fit	O
on	O
the	O
earlier	O
cameras	O
.	O
</s>
<s>
The	O
flange	O
focal	O
distance	O
between	O
mount	B-Algorithm
and	O
film	O
is	O
47mm	O
.	O
</s>
<s>
On	O
5	O
March	O
2009	O
,	O
Leica	O
announced	O
plans	O
to	O
cease	O
production	O
of	O
its	O
R-Series	B-Algorithm
manual	O
focus	O
SLR	B-Algorithm
and	O
lenses	O
.	O
</s>
<s>
Based	O
on	O
the	O
Minolta	O
XE.center	O
|120pxLeica	O
R41980	O
–	O
1986ManualAperture	O
priority	O
semi	O
automaticShutter	O
priority	O
semi	O
automaticProgram	O
automatic	O
Based	O
on	O
the	O
Minolta	O
Minolta	O
XD-7.center	O
|120pxLeica	O
R51986	O
–	O
1991ManualAperture	O
priority	O
semi	O
automaticShutter	O
priority	O
semi	O
automaticProgram	O
automatic	O
Automatic	O
TTL	O
flash	O
exposure	O
measurement	O
center|120pxLeica	O
R61987	O
–	O
1996Manual	O
Mechanical	O
shutter	O
,	O
relied	O
on	O
battery	O
power	O
only	O
for	O
the	O
built-in	O
light	O
meter.center	O
|120pxLeica	O
R71991	O
–	O
1996ManualAperture	O
priority	O
semi	O
automaticShutter	O
priority	O
semi	O
automaticProgram	O
automatic	O
Complete	O
flash	O
automation.center	O
|120pxLeica	O
R81996	O
–	O
2002ManualAperture	O
priority	O
semi	O
automaticShutter	O
priority	O
semi	O
automaticProgram	O
fully	O
automaticFlash	O
pre	O
exposure	O
measurement	O
Intended	O
as	O
a	O
clean	O
break	O
from	O
the	O
previous	O
generation	O
of	O
Leica	B-Algorithm
R	I-Algorithm
cameras	O
and	O
designed	O
in	O
house.center	O
|120pxLeica	O
R92002	O
–	O
2009ManualAperture	O
priority	O
semi	O
automaticShutter	O
priority	O
semi	O
automaticProgram	O
fully	O
automaticFlash	O
pre	O
exposure	O
measurement	O
Electronic	O
changes	O
included	O
the	O
ability	O
to	O
tune	O
the	O
sensitivity	O
of	O
matrix	O
metering	O
.	O
</s>
<s>
The	O
original	O
Leicaflex	B-Algorithm
1	O
cam	O
lenses	O
have	O
a	O
single	O
sloped	O
cam	O
that	O
communicates	O
aperture	O
setting	O
to	O
the	O
camera	O
.	O
</s>
<s>
They	O
can	O
be	O
used	O
on	O
later	O
SL	B-Algorithm
/	O
SL2	B-Algorithm
and	O
R-series	B-Algorithm
cameras	O
in	O
stop-down	O
metering	O
mode	O
only	O
.	O
</s>
<s>
Leica	O
do	O
not	O
recommend	O
that	O
1	O
cam	O
lenses	O
be	O
used	O
on	O
R8	B-Algorithm
or	O
R9	B-Algorithm
cameras	O
because	O
of	O
possible	O
damage	O
to	O
the	O
cameras	O
 '	O
ROM	O
contacts	O
.	O
</s>
<s>
2	O
cam	O
lenses	O
have	O
two	O
sloped	O
cams	O
for	O
the	O
Leicaflex	B-Algorithm
SL	I-Algorithm
and	O
SL2	B-Algorithm
with	O
TTL	O
metering	O
and	O
are	O
fully	O
compatible	O
with	O
the	O
original	O
Leicaflex	B-Algorithm
.	O
</s>
<s>
They	O
can	O
be	O
used	O
on	O
R	B-Algorithm
series	I-Algorithm
cameras	O
with	O
the	O
same	O
limitation	O
and	O
warning	O
as	O
1	O
cam	O
lenses	O
and	O
may	O
also	O
be	O
fitted	O
with	O
later	O
cams	O
.	O
</s>
<s>
3	O
cam	O
lenses	O
were	O
introduced	O
with	O
R	B-Algorithm
series	I-Algorithm
cameras	O
and	O
have	O
the	O
earlier	O
sloped	O
cams	O
and	O
a	O
third	O
stepped	O
"	O
R-Cam	O
"	O
that	O
communicates	O
aperture	O
information	O
.	O
</s>
<s>
They	O
will	O
work	O
with	O
all	O
Leica	O
SLR	B-Algorithm
models	O
since	O
they	O
have	O
all	O
three	O
mechanical	O
connections	O
.	O
</s>
<s>
These	O
lenses	O
only	O
have	O
the	O
stepped	O
R-cam	O
and	O
only	O
work	O
on	O
R-series	B-Algorithm
cameras	O
.	O
</s>
<s>
The	O
mount	B-Algorithm
is	O
deliberately	O
slightly	O
incompatible	O
with	O
Leicaflex	B-Algorithm
models	O
and	O
will	O
not	O
fit	O
.	O
</s>
<s>
This	O
is	O
only	O
supported	O
on	O
the	O
R8/R9	O
although	O
the	O
lenses	O
are	O
fully	O
compatible	O
with	O
all	O
R-series	B-Algorithm
cameras	O
.	O
</s>
<s>
Earlier	O
1	O
,	O
2	O
,	O
or	O
3	O
cam	O
lenses	O
may	O
be	O
upgraded	O
to	O
ROM	O
but	O
this	O
entails	O
removal	O
of	O
both	O
sloped	O
cams	O
,	O
meaning	O
that	O
the	O
lens	O
will	O
no	O
longer	O
be	O
compatible	O
with	O
Leicaflex	B-Algorithm
series	O
cameras	O
.	O
</s>
<s>
The	O
flange	O
focal	O
distance	O
of	O
47mm	O
is	O
fairly	O
large	O
,	O
meaning	O
that	O
few	O
other	O
systems	O
 '	O
lenses	O
can	O
be	O
adapted	O
to	O
fit	O
on	O
a	O
Leica	B-Algorithm
R	I-Algorithm
and	O
retain	O
infinity	O
focus	O
,	O
but	O
R	O
lenses	O
can	O
be	O
converted	O
to	O
other	O
systems	O
.	O
</s>
<s>
The	O
distance	O
is	O
only	O
0.5mm	O
larger	O
than	O
the	O
Nikon	B-Architecture
F-mount	I-Architecture
,	O
which	O
is	O
not	O
sufficient	O
to	O
make	O
a	O
workable	O
adapter	O
,	O
however	O
,	O
at	O
least	O
one	O
Nikon	O
camera	O
has	O
been	O
modified	O
with	O
a	O
Leica	B-Algorithm
R	I-Algorithm
bayonet	I-Algorithm
mount	B-Algorithm
to	O
take	O
R	O
lenses	O
,	O
and	O
at	O
least	O
two	O
manufacturers	O
make	O
replacement	O
mounts	O
,	O
allowing	O
many	O
Leica	B-Algorithm
R	I-Algorithm
lenses	O
to	O
be	O
used	O
directly	O
on	O
various	O
camera	O
systems	O
,	O
such	O
as	O
Nikon	B-Architecture
F	I-Architecture
mount	I-Architecture
cameras	O
.	O
</s>
<s>
A	O
further	O
point	O
of	O
consideration	O
is	O
whether	O
the	O
protrusion	O
on	O
the	O
rear	O
lens	O
block	O
will	O
engage	O
with	O
the	O
mirror	O
of	O
the	O
target	O
SLR	B-Algorithm
.	O
</s>
<s>
A	O
number	O
of	O
manufacturers	O
have	O
produced	O
adapters	O
to	O
allow	O
Canon	B-Algorithm
EOS	I-Algorithm
cameras	O
to	O
take	O
R	O
lenses	O
,	O
these	O
operate	O
only	O
in	O
stop-down	O
metering	O
mode	O
but	O
function	O
well	O
when	O
rapid	O
operation	O
is	O
not	O
required	O
.	O
</s>
