<s>
The	O
Sigma	O
SA-mount	O
is	O
a	O
lens	B-Algorithm
mount	I-Algorithm
by	O
the	O
Sigma	O
Corporation	O
of	O
Japan	O
for	O
use	O
on	O
their	O
autofocus	O
single-lens	B-Algorithm
reflex	I-Algorithm
and	O
mirrorless	B-Device
cameras	I-Device
.	O
</s>
<s>
Originally	O
,	O
the	O
SA-mount	O
was	O
a	O
dual-bayonet	O
mount	O
with	O
inner	O
(	O
SA-IB	O
)	O
and	O
outer	O
(	O
SA-OB	O
)	O
bayonets	O
,	O
the	O
latter	O
being	O
a	O
feature	O
intended	O
to	O
mount	O
heavy	O
telephoto	O
lenses	O
,	O
but	O
never	O
utilized	O
by	O
Sigma	O
and	O
consequently	O
dropped	O
with	O
the	O
release	O
of	O
the	O
SD14	B-Algorithm
in	O
2007	O
.	O
</s>
<s>
There	O
were	O
two	O
precursors	O
to	O
the	O
introduction	O
of	O
SA-mount	O
cameras	O
,	O
the	O
manual-focus	O
Sigma	O
Mark-I	O
in	O
1976	O
,	O
which	O
still	O
featured	O
a	O
M42	B-Algorithm
screw	I-Algorithm
lens	I-Algorithm
mount	I-Algorithm
,	O
and	O
the	O
SA-1	O
of	O
1983	O
with	O
Pentax	B-Algorithm
K-mount	I-Algorithm
.	O
</s>
<s>
Mechanically	O
,	O
the	O
(	O
inner	O
)	O
SA-mount	O
is	O
similar	O
to	O
the	O
Pentax	B-Algorithm
K-mount	I-Algorithm
as	O
well	O
,	O
but	O
with	O
a	O
flange	O
focal	O
distance	O
of	O
44.00mm	O
,	O
identical	O
to	O
that	O
of	O
the	O
Canon	B-Application
EF-mount	I-Application
.	O
</s>
<s>
Like	O
the	O
EF-mount	B-Application
,	O
the	O
SA-mount	O
uses	O
electrical	O
communication	O
between	O
body	O
and	O
lens	O
,	O
and	O
in	O
fact	O
uses	O
the	O
same	O
signalling	O
lines	O
and	O
protocol	O
as	O
the	O
EF-mount	B-Application
,	O
despite	O
the	O
physical	O
incompatibility	O
.	O
</s>
<s>
Sigma	O
has	O
long	O
produced	O
EF-mount	B-Application
lenses	O
for	O
Canon	O
cameras	O
,	O
and	O
thus	O
had	O
the	O
ability	O
to	O
use	O
this	O
protocol	O
.	O
</s>
<s>
All	O
Sigma	O
SLRs	B-Algorithm
and	O
DSLRs	O
can	O
use	O
manual	O
focus	O
lenses	O
too	O
,	O
which	O
have	O
no	O
electrical	O
communication	O
between	O
body	O
and	O
lens	O
.	O
</s>
<s>
In	O
September	O
2018	O
,	O
Sigma	O
announced	O
that	O
they	O
will	O
stop	O
the	O
development	O
of	O
SA-mount	O
cameras	O
and	O
focus	O
on	O
the	O
Leica	B-Algorithm
L-mount	I-Algorithm
,	O
as	O
members	O
of	O
the	O
L-Mount	B-Algorithm
Alliance	I-Algorithm
alongside	O
Panasonic	O
.	O
</s>
<s>
M42-mount	B-Algorithm
lenses	O
can	O
be	O
mounted	O
via	O
adapters	O
utilizing	O
the	O
SA	O
inner	O
bayonet	O
.	O
</s>
<s>
Despite	O
of	O
the	O
physical	O
similarities	O
Pentax	B-Algorithm
K-mount	I-Algorithm
(	O
PK	O
)	O
lenses	O
ca	O
n't	O
really	O
be	O
fitted	O
straight	O
onto	O
the	O
SA-mount	O
as	O
well	O
,	O
once	O
the	O
protruding	O
AA	O
lever	O
and	O
AA	O
protector	O
outcrop	O
are	O
removed	O
,	O
though	O
the	O
fit	O
is	O
slightly	O
loose	O
as	O
the	O
SA-mount	O
has	O
a	O
slightly	O
bigger	O
bore	O
than	O
the	O
PK-mount	O
.	O
</s>
<s>
Utilizing	O
the	O
SA-OB	O
bayonet	O
mount	O
(	O
on	O
camera	O
bodies	O
supporting	O
it	O
)	O
,	O
Nikon	B-Architecture
F-mount	I-Architecture
can	O
be	O
fitted	O
and	O
used	O
via	O
a	O
JTAT	O
mount	O
adapter	O
developed	O
by	O
Kazuo	O
Suzuki	O
,	O
Tachibana	O
Seisakusho	O
.	O
</s>
<s>
Newer	O
lenses	O
with	O
Sigma	O
SA-mount	O
can	O
be	O
used	O
on	O
newer	O
Sony	B-Algorithm
E-mount	I-Algorithm
cameras	O
(	O
for	O
example	O
,	O
the	O
Sony	B-Device
ILCE-7	I-Device
series	O
,	O
the	O
ILCE-5000	B-Algorithm
,	O
ILCE-6000	B-Algorithm
etc	O
.	O
)	O
</s>
<s>
(	O
A	O
similar	O
Sigma	O
MC-11	O
EF-E	O
adapter	O
is	O
available	O
to	O
mount	O
Canon	B-Application
EF-mount	I-Application
lenses	O
on	O
Sony	B-Algorithm
E-mount	I-Algorithm
cameras	O
.	O
)	O
</s>
<s>
All	O
SLR	B-Algorithm
lenses	O
manufactured	O
by	O
Sigma	O
since	O
1993	O
are	O
available	O
for	O
the	O
SA-mount	O
.	O
</s>
