<s>
The	O
Leica	B-Algorithm
M	I-Algorithm
mount	I-Algorithm
is	O
a	O
camera	O
lens	B-Algorithm
mount	I-Algorithm
introduced	O
in	O
1954	O
with	O
the	O
Leica	B-Algorithm
M3	I-Algorithm
,	O
and	O
a	O
range	O
of	O
lenses	O
.	O
</s>
<s>
Visoflex	O
reflex	O
viewing	O
attachment	O
)	O
up	O
to	O
the	O
current	O
film	O
Leica	B-Algorithm
M-A	I-Algorithm
and	O
digital	B-Device
Leica	B-Algorithm
M11	I-Algorithm
cameras	O
.	O
</s>
<s>
This	O
lens	B-Algorithm
mount	I-Algorithm
has	O
also	O
been	O
used	O
by	O
Epson	O
,	O
Ricoh	O
,	O
Minolta	O
,	O
Konica	O
,	O
Cosina	B-Algorithm
Voigtländer	I-Algorithm
,	O
Rollei	O
,	O
Carl	O
Zeiss	O
AG	O
and	O
Rollei	O
Fototechnic	O
on	O
some	O
of	O
their	O
cameras	O
.	O
</s>
<s>
The	O
Leica	B-Algorithm
M	I-Algorithm
mount	I-Algorithm
was	O
introduced	O
in	O
1954	O
at	O
that	O
year	O
's	O
Photokina	O
show	O
,	O
with	O
the	O
Leica	B-Algorithm
M3	I-Algorithm
as	O
its	O
first	O
camera	O
.	O
</s>
<s>
The	O
'	O
M	O
 '	O
stands	O
for	O
Messsucher	O
or	O
rangefinder	B-Algorithm
in	O
German	O
.	O
</s>
<s>
This	O
new	O
camera	O
abandoned	O
the	O
M39	B-Algorithm
lens	I-Algorithm
mount	I-Algorithm
in	O
favour	O
of	O
a	O
new	O
bayonet	O
mount	O
.	O
</s>
<s>
Other	O
innovations	O
introduced	O
by	O
the	O
M3	O
included	O
a	O
single	O
window	O
for	O
the	O
viewfinder	O
(	O
for	O
composition	O
)	O
and	O
the	O
rangefinder	B-Algorithm
(	O
for	O
focusing	O
)	O
.	O
</s>
<s>
With	O
the	O
introduction	O
of	O
the	O
Through-the-lens	O
metering	O
(	O
TTL	O
)	O
in	O
the	O
Leica	B-Algorithm
M5	I-Algorithm
and	O
the	O
digital	B-Device
Leica	B-Algorithm
M8	I-Algorithm
being	O
the	O
most	O
notable	O
innovations	O
since	O
then	O
.	O
</s>
<s>
These	O
lenses	O
are	O
divided	O
by	O
Leica	O
based	O
on	O
their	O
maximum	O
aperture	B-General_Concept
number	O
(	O
also	O
known	O
as	O
f-number	O
)	O
.	O
</s>
<s>
+Summary	O
of	O
Leica	B-Algorithm
M	I-Algorithm
lensesSpeedName21mm24mm28mm35mm50mm75mm90mm135mm	O
Summaron	O
Super-Angulon	O
Macro	O
Elmar	O
Elmar	O
Tele-Elmar	O
Tri-Elmar	O
ASPH16-18-21mm28-35-50mm	O
Elmar	O
ASPH	O
.	O
</s>
