<s>
The	O
Mamiya	B-Algorithm
Six	I-Algorithm
,	O
also	O
known	O
as	O
the	O
Mamiya-6	O
,	O
is	O
a	O
series	O
of	O
folding	B-Algorithm
medium-format	O
rangefinder	B-Algorithm
cameras	I-Algorithm
manufactured	O
by	O
Mamiya	O
between	O
1940	O
and	O
the	O
late	O
1950s	O
.	O
</s>
<s>
The	O
cameras	O
were	O
coupled	B-Algorithm
rangefinders	I-Algorithm
,	O
but	O
had	O
a	O
unique	O
focusing	O
mechanism	O
that	O
moved	O
the	O
film	O
plane	O
instead	O
of	O
the	O
lens	O
.	O
</s>
<s>
Beginning	O
with	O
the	O
model	O
IV	O
,	O
the	O
name	O
on	O
the	O
top	O
plate	O
changed	O
from	O
"	O
Mamiya	B-Algorithm
Six	I-Algorithm
"	O
(	O
two	O
lines	O
)	O
to	O
"	O
Mamiya-6	O
"	O
.	O
</s>
