<s>
This	O
article	O
is	O
about	O
photographic	O
lenses	O
for	O
single-lens	B-Algorithm
reflex	I-Algorithm
film	O
cameras	O
(	O
SLRs	B-Algorithm
)	O
and	O
digital	B-Device
single-lens	I-Device
reflex	I-Device
cameras	I-Device
(	O
DSLRs	B-Device
)	O
.	O
</s>
<s>
Emphasis	O
is	O
on	O
modern	O
lenses	O
for	O
35	O
mm	O
film	O
SLRs	B-Algorithm
and	O
for	O
DSLRs	B-Device
with	O
sensor	B-Algorithm
sizes	I-Algorithm
less	O
than	O
or	O
equal	O
to	O
35mm	O
(	O
"	O
full-frame	B-Algorithm
"	O
)	O
.	O
</s>
<s>
Most	O
SLR	B-Algorithm
and	O
DSLR	B-Device
cameras	I-Device
provide	O
the	O
option	O
of	O
changing	O
the	O
lens	O
.	O
</s>
<s>
Film	O
SLR	B-Algorithm
cameras	I-Algorithm
have	O
existed	O
since	O
the	O
late	O
1950s	O
,	O
and	O
over	O
the	O
years	O
a	O
very	O
large	O
number	O
of	O
different	O
lenses	O
have	O
been	O
produced	O
,	O
both	O
by	O
camera	O
manufacturers	O
(	O
who	O
typically	O
only	O
make	O
lenses	O
intended	O
for	O
their	O
own	O
camera	O
bodies	O
)	O
and	O
by	O
third-party	O
optics	O
companies	O
who	O
may	O
make	O
lenses	O
for	O
several	O
different	O
camera	O
lines	O
.	O
</s>
<s>
DSLRs	B-Device
became	O
affordable	O
around	O
the	O
mid-1990s	O
,	O
and	O
have	O
become	O
extremely	O
popular	O
in	O
recent	O
years	O
.	O
</s>
<s>
Some	O
manufacturers	O
,	O
for	O
example	O
Minolta	O
,	O
Canon	O
and	O
Nikon	B-Algorithm
,	O
chose	O
to	O
make	O
their	O
DSLRs	B-Device
100%	O
compatible	O
with	O
their	O
existing	O
SLR	B-Algorithm
lenses	O
in	O
the	O
beginning	O
,	O
allowing	O
owners	O
of	O
new	O
DSLRs	B-Device
to	O
continue	O
to	O
use	O
their	O
existing	O
lenses	O
and	O
get	O
a	O
longer	O
lifespan	O
from	O
their	O
investment	O
.	O
</s>
<s>
Others	O
,	O
for	O
example	O
Olympus	O
,	O
chose	O
to	O
create	O
a	O
completely	O
new	O
lens	B-Algorithm
mount	I-Algorithm
and	O
series	O
of	O
lenses	O
for	O
their	O
DSLRs	B-Device
.	O
</s>
<s>
The	O
Pentax	B-Application
SLR	B-Algorithm
camera	I-Algorithm
K-mount	B-Algorithm
system	O
is	O
backward	O
compatible	O
to	O
all	O
previous	O
lens	O
generations	O
from	O
Pentax	B-Application
,	O
including	O
the	O
latest	O
digital	B-Device
SLRs	I-Device
like	O
the	O
K-3	B-Algorithm
and	O
K-50	B-Algorithm
.	O
</s>
<s>
A	O
Pentax	B-Algorithm
K-mount	I-Algorithm
lens	O
from	O
the	O
early	O
70s	O
can	O
be	O
used	O
on	O
the	O
newest	O
Pentax	B-Application
DSLR	B-Device
although	O
it	O
may	O
not	O
provide	O
features	O
that	O
are	O
included	O
in	O
newer	O
lenses	O
(	O
e.g.	O
</s>
<s>
There	O
are	O
a	O
few	O
exceptions	O
from	O
the	O
MZ	O
and	O
ZX	O
series	O
of	O
Pentax	B-Application
film	O
cameras	O
that	O
do	O
not	O
work	O
with	O
some	O
of	O
the	O
older	O
lenses	O
.	O
</s>
<s>
As	O
implied	O
by	O
the	O
above	O
,	O
lenses	O
are	O
only	O
directly	O
interchangeable	O
within	O
the	O
"	O
mount	B-Algorithm
system	I-Algorithm
"	O
for	O
which	O
they	O
are	O
built	O
.	O
</s>
<s>
lack	O
of	O
autofocus	O
or	O
automatic	O
aperture	B-General_Concept
control	O
)	O
.	O
</s>
<s>
Further	O
,	O
in	O
some	O
cases	O
the	O
adapter	O
will	O
require	O
an	O
additional	O
optical	O
element	O
to	O
correct	O
for	O
varied	O
registration	O
distances	O
(	O
the	O
distance	O
from	O
the	O
rear	O
of	O
the	O
mount	O
to	O
the	O
focal	O
plane	O
on	O
the	O
image	B-Algorithm
sensor	I-Algorithm
or	O
film	O
)	O
.	O
</s>
<s>
Adapters	O
may	O
not	O
be	O
available	O
to	O
bridge	O
every	O
combination	O
of	O
lens	B-Algorithm
mount	I-Algorithm
and	O
camera	O
mount	O
.	O
</s>
<s>
The	O
aperture	B-General_Concept
of	O
a	O
lens	O
is	O
the	O
opening	O
that	O
regulates	O
the	O
amount	O
of	O
light	O
that	O
passes	O
through	O
the	O
lens	O
.	O
</s>
<s>
The	O
relative	O
aperture	B-General_Concept
is	O
specified	O
as	O
an	O
f-number	O
,	O
the	O
ratio	O
of	O
the	O
lens	O
focal	B-Algorithm
length	I-Algorithm
to	O
its	O
effective	O
aperture	B-General_Concept
diameter	O
.	O
</s>
<s>
A	O
small	O
f-number	O
like	O
2.0	O
indicates	O
a	O
large	O
aperture	B-General_Concept
(	O
more	O
light	O
passes	O
through	O
)	O
,	O
while	O
a	O
large	O
f-number	O
like	O
22	O
indicates	O
a	O
small	O
aperture	B-General_Concept
(	O
little	O
light	O
passes	O
through	O
)	O
.	O
</s>
<s>
Aperture	B-General_Concept
settings	O
are	O
usually	O
not	O
continuously	O
variable	O
;	O
instead	O
the	O
diaphragm	O
has	O
typically	O
5	O
–	O
10	O
discrete	O
settings	O
.	O
</s>
<s>
A	O
"	O
slow	O
"	O
lens	O
(	O
one	O
that	O
is	O
not	O
capable	O
of	O
passing	O
a	O
lot	O
of	O
light	O
through	O
)	O
might	O
have	O
a	O
maximum	O
aperture	B-General_Concept
from	O
5.6	O
to	O
11	O
,	O
while	O
a	O
"	O
fast	O
"	O
lens	O
(	O
one	O
that	O
can	O
pass	O
more	O
light	O
through	O
)	O
might	O
have	O
a	O
maximum	O
aperture	B-General_Concept
from	O
1	O
to	O
4	O
.	O
</s>
<s>
Fast	O
lenses	O
are	O
by	O
definition	O
larger	O
than	O
slow	O
lenses	O
(	O
for	O
comparable	O
focal	B-Algorithm
length	I-Algorithm
)	O
,	O
and	O
typically	O
cost	O
more	O
.	O
</s>
<s>
The	O
aperture	B-General_Concept
affects	O
not	O
only	O
the	O
amount	O
of	O
light	O
that	O
passes	O
through	O
the	O
lens	O
,	O
but	O
also	O
the	O
depth	O
of	O
field	O
of	O
the	O
resulting	O
image	O
:	O
a	O
larger	O
aperture	B-General_Concept
(	O
a	O
smaller	O
f-number	O
,	O
e.g.	O
</s>
<s>
f/2.0	O
)	O
will	O
have	O
a	O
shallow	O
depth	O
of	O
field	O
,	O
while	O
a	O
smaller	O
aperture	B-General_Concept
(	O
a	O
larger	O
f-number	O
,	O
e.g.	O
</s>
<s>
The	O
focal	B-Algorithm
length	I-Algorithm
of	O
a	O
lens	O
,	O
together	O
with	O
the	O
size	O
of	O
the	O
image	B-Algorithm
sensor	I-Algorithm
in	O
the	O
camera	O
(	O
or	O
size	O
of	O
the	O
35	O
mm	O
film	O
)	O
,	O
determines	O
the	O
angle	O
of	O
view	O
.	O
</s>
<s>
A	O
lens	O
is	O
considered	O
to	O
be	O
a	O
"	O
normal	O
lens	O
"	O
,	O
in	O
terms	O
of	O
its	O
angle	O
of	O
view	O
on	O
a	O
camera	O
,	O
when	O
its	O
focal	B-Algorithm
length	I-Algorithm
is	O
approximately	O
equal	O
to	O
the	O
diagonal	O
dimension	O
of	O
the	O
film	O
format	O
or	O
image	B-Algorithm
sensor	I-Algorithm
format	I-Algorithm
.	O
</s>
<s>
A	O
wide-angle	O
lens	O
has	O
a	O
shorter	O
focal	B-Algorithm
length	I-Algorithm
,	O
and	O
includes	O
more	O
of	O
the	O
viewed	O
scene	O
than	O
a	O
normal	O
lens	O
;	O
a	O
telephoto	O
lens	O
has	O
a	O
longer	O
focal	B-Algorithm
length	I-Algorithm
,	O
and	O
images	O
a	O
small	O
portion	O
of	O
the	O
scene	O
,	O
making	O
it	O
seem	O
closer	O
.	O
</s>
<s>
Lenses	O
are	O
not	O
labeled	O
or	O
sold	O
according	O
to	O
their	O
angle	O
of	O
view	O
,	O
but	O
rather	O
by	O
their	O
focal	B-Algorithm
length	I-Algorithm
,	O
usually	O
expressed	O
in	O
millimeters	O
.	O
</s>
<s>
But	O
this	O
specification	O
is	O
insufficient	O
to	O
compare	O
lenses	O
for	O
different	O
cameras	O
because	O
field	O
of	O
view	O
also	O
depends	O
on	O
the	O
sensor	B-Algorithm
size	I-Algorithm
.	O
</s>
<s>
For	O
example	O
,	O
a	O
50mm	O
lens	O
mounted	O
on	O
a	O
Nikon	B-Algorithm
D3	I-Algorithm
(	O
a	O
full-frame	B-Algorithm
camera	I-Algorithm
)	O
provides	O
approximately	O
the	O
same	O
field	O
of	O
view	O
as	O
a	O
32mm	O
lens	O
mounted	O
on	O
a	O
Sony	B-Device
α100	I-Device
(	O
an	O
APS-C	B-Algorithm
camera	O
)	O
.	O
</s>
<s>
For	O
example	O
,	O
a	O
35mm	O
lens	O
mounted	O
on	O
a	O
Canon	B-Algorithm
EOS	I-Algorithm
5D	I-Algorithm
(	O
full-frame	B-Algorithm
)	O
provides	O
a	O
slightly	O
wide-angle	O
view	O
,	O
while	O
the	O
same	O
lens	O
mounted	O
on	O
a	O
Canon	B-Algorithm
EOS	I-Algorithm
400D	I-Algorithm
(	O
APS-C	B-Algorithm
)	O
provides	O
a	O
"	O
normal	O
"	O
or	O
slightly	O
telephoto	O
view	O
.	O
</s>
<s>
In	O
order	O
to	O
make	O
it	O
easier	O
to	O
compare	O
lens	O
–	O
camera	O
pairs	O
,	O
it	O
is	O
common	O
to	O
talk	O
about	O
their	O
35	O
mm	O
equivalent	O
focal	B-Algorithm
length	I-Algorithm
.	O
</s>
<s>
For	O
example	O
,	O
when	O
talking	O
about	O
a	O
14mm	O
lens	O
for	O
a	O
Four	B-Architecture
Thirds	I-Architecture
System	I-Architecture
camera	O
,	O
one	O
would	O
not	O
only	O
indicate	O
that	O
it	O
had	O
a	O
focal	B-Algorithm
length	I-Algorithm
of	O
14mm	O
,	O
but	O
also	O
that	O
its	O
"	O
35mm	O
equivalent	O
focal	B-Algorithm
length	I-Algorithm
"	O
is	O
28mm	O
.	O
</s>
<s>
This	O
way	O
of	O
talking	O
about	O
lenses	O
is	O
not	O
just	O
limited	O
to	O
SLR	B-Algorithm
and	O
DSLR	B-Device
lenses	O
;	O
it	O
is	O
very	O
common	O
to	O
see	O
this	O
focal	B-Algorithm
length	I-Algorithm
equivalency	O
in	O
the	O
specification	O
of	O
the	O
lens	O
on	O
a	O
digicam	O
.	O
</s>
<s>
Sensor	B-Algorithm
size	I-Algorithm
:	O
35	O
mm	O
or	O
full-frame	B-Algorithm
APS-H	O
APS-C	B-Algorithm
Foveon	O
X3The	O
crop	O
factor	O
in	O
this	O
column	O
refers	O
to	O
the	O
original	O
Foveon	B-Algorithm
X3	I-Algorithm
sensor	I-Algorithm
.	O
</s>
<s>
Current	O
versions	O
of	O
the	O
Foveon	B-Algorithm
X3	I-Algorithm
are	O
standard	O
APS-C	B-Algorithm
size	O
with	O
a	O
1.5	O
crop	O
factor	O
.	O
</s>
<s>
Four	B-Architecture
Thirds	I-Architecture
Crop	O
factor	O
:	O
1.0	O
1.3	O
1.5	O
or	O
1.6	O
1.7	O
2.0	O
Lens	O
view	O
Angle	O
of	O
view( deg	O
.	O
</s>
<s>
The	O
focal	B-Algorithm
length	I-Algorithm
of	O
a	O
zoom	O
lens	O
is	O
not	O
fixed	O
;	O
instead	O
it	O
can	O
be	O
varied	O
between	O
a	O
specified	O
minimum	O
and	O
maximum	O
value	O
.	O
</s>
<s>
Modern	O
lens	O
technology	O
is	O
such	O
that	O
the	O
loss	O
of	O
image	O
quality	O
in	O
zoom	O
lenses	O
(	O
relative	O
to	O
non-zoom	O
lenses	O
)	O
is	O
minimal	O
,	O
and	O
zoom	O
lenses	O
have	O
become	O
the	O
standard	O
lenses	O
for	O
SLRs	B-Algorithm
and	O
DSLRs	B-Device
.	O
</s>
<s>
However	O
,	O
zoom	O
lenses	O
still	O
typically	O
have	O
a	O
lower	O
maximum	O
aperture	B-General_Concept
than	O
fixed-focal	O
(	O
"	O
prime	O
"	O
)	O
lenses	O
for	O
the	O
same	O
weight	O
and	O
cost	O
,	O
especially	O
for	O
shorter	O
focal	B-Algorithm
lengths	I-Algorithm
.	O
</s>
<s>
Zoom	O
lenses	O
are	O
often	O
described	O
by	O
the	O
ratio	O
of	O
their	O
longest	O
to	O
shortest	O
focal	B-Algorithm
lengths	I-Algorithm
.	O
</s>
<s>
For	O
example	O
,	O
a	O
zoom	O
lens	O
with	O
focal	B-Algorithm
lengths	I-Algorithm
ranging	O
from	O
100mm	O
to	O
400mm	O
may	O
be	O
described	O
as	O
a	O
4:1	O
or	O
"	O
4×	O
"	O
zoom	O
.	O
</s>
<s>
The	O
maximum	O
aperture	B-General_Concept
for	O
a	O
zoom	O
lens	O
may	O
be	O
the	O
same	O
(	O
constant	O
)	O
for	O
all	O
focal	B-Algorithm
lengths	I-Algorithm
,	O
but	O
it	O
is	O
more	O
common	O
that	O
the	O
maximum	O
aperture	B-General_Concept
is	O
greater	O
at	O
the	O
wide-angle	O
end	O
than	O
at	O
the	O
telephoto	O
end	O
of	O
the	O
zoom	O
range	O
.	O
</s>
<s>
For	O
example	O
,	O
a	O
100mm	O
to	O
400mm	O
lens	O
may	O
have	O
a	O
maximum	O
aperture	B-General_Concept
of	O
f/4.0	O
at	O
the	O
100mm	O
end	O
but	O
will	O
diminish	O
to	O
only	O
f/5.6	O
at	O
the	O
400mm	O
end	O
of	O
the	O
zoom	O
range	O
.	O
</s>
<s>
Zoom	O
lenses	O
with	O
constant	O
maximum	O
apertures	B-General_Concept
(	O
such	O
as	O
f/2.8	O
for	O
a	O
24	O
–	O
70mm	O
lens	O
)	O
are	O
usually	O
reserved	O
for	O
lenses	O
with	O
higher	O
build	O
quality	O
and	O
are	O
thus	O
more	O
expensive	O
than	O
those	O
with	O
variable	O
maximum	O
apertures	B-General_Concept
.	O
</s>
<s>
Most	O
users	O
of	O
SLR	B-Algorithm
and	O
DSLR	B-Device
cameras	I-Device
stick	O
to	O
using	O
zoom	O
lenses	O
,	O
while	O
a	O
few	O
of	O
the	O
more	O
adventurous	O
amateurs	O
and	O
many	O
professional	O
photographers	O
also	O
invest	O
in	O
a	O
few	O
prime	O
lenses	O
.	O
</s>
<s>
Perspective	O
control	O
lenses	O
and	O
soft-focus	O
lenses	O
,	O
were	O
more	O
popular	O
with	O
film	O
SLRs	B-Algorithm
but	O
are	O
less	O
popular	O
for	O
DSLRs	B-Device
because	O
the	O
same	O
or	O
similar	O
results	O
can	O
be	O
obtained	O
with	O
post-processing	B-Application
software	I-Application
.	O
</s>
<s>
Almost	O
all	O
modern	O
lenses	O
for	O
SLRs	B-Algorithm
and	O
DSLRs	B-Device
provide	O
automatic	O
focus	O
.	O
</s>
<s>
The	O
autofocus	O
sensor(s )	O
and	O
electronics	O
are	O
actually	O
in	O
the	O
camera	O
body	O
,	O
and	O
this	O
circuitry	O
provides	O
electrical	O
power	O
and	O
signals	O
to	O
a	O
motor	O
inside	O
the	O
lens	O
that	O
adjusts	O
the	O
focus	O
.	O
</s>
<s>
These	O
ultrasonic	O
drives	O
go	O
by	O
different	O
names	O
according	O
to	O
the	O
manufacturer	O
,	O
for	O
example	O
USM	O
(	O
Canon	O
)	O
,	O
AF-S/Silent	O
Wave	O
(	O
Nikon	B-Algorithm
)	O
,	O
Super	O
Sonicwave	O
Motor/SSM	O
(	O
Sony	O
)	O
,	O
Supersonic	O
Wave	O
Drive	O
(	O
Olympus	O
)	O
,	O
Extra	O
Silent	O
Motor	O
(	O
Panasonic/Leica	O
)	O
,	O
Supersonic	O
Drive	O
Motor	O
(	O
Pentax	B-Application
)	O
,	O
and	O
Hypersonic	O
Motor/HSM	O
(	O
Sigma	O
)	O
.	O
</s>
<s>
There	O
are	O
two	O
kinds	O
of	O
image	O
stabilization	O
used	O
in	O
SLR	B-Algorithm
and	O
DSLR	B-Device
cameras	I-Device
and	O
their	O
lenses	O
:	O
</s>
<s>
In-body	O
image	O
stabilization	O
is	O
implemented	O
by	O
moving	O
the	O
image	B-Algorithm
sensor	I-Algorithm
in	O
an	O
attempt	O
to	O
counteract	O
the	O
sensed	O
motion	O
of	O
the	O
camera	O
.	O
</s>
<s>
The	O
advantage	O
of	O
this	O
technique	O
is	O
that	O
it	O
works	O
for	O
all	O
lenses	O
mounted	O
on	O
the	O
camera	O
,	O
at	O
least	O
if	O
the	O
camera	O
electronics	O
are	O
aware	O
of	O
the	O
lens	O
 '	O
focal	B-Algorithm
length	I-Algorithm
.	O
</s>
<s>
This	O
is	O
most	O
commonly	O
done	O
automatically	O
,	O
but	O
some	O
cameras	O
(	O
such	O
as	O
all	O
Olympus	O
bodies	O
with	O
IS	O
)	O
allow	O
the	O
user	O
to	O
input	O
the	O
focal	B-Algorithm
length	I-Algorithm
manually	O
for	O
use	O
with	O
lenses	O
with	O
no	O
electronic	O
coupling	O
.	O
</s>
<s>
In-body	O
image	O
stabilization	O
is	O
used	O
in	O
modern	O
Olympus	O
,	O
Sony	O
,	O
and	O
Pentax	B-Application
cameras	I-Application
.	O
</s>
<s>
Panasonic	O
,	O
Canon	O
,	O
and	O
Nikon	B-Algorithm
use	O
lens-based	O
image	O
stabilization	O
.	O
</s>
<s>
There	O
is	O
almost	O
no	O
commonality	O
between	O
different	O
camera	O
makers	O
regarding	O
lens	B-Algorithm
mount	I-Algorithm
systems	O
.	O
</s>
<s>
Each	O
manufacturer	O
has	O
developed	O
their	O
own	O
system	O
,	O
and	O
build	O
camera	O
bodies	O
and	O
lenses	O
that	O
only	O
work	O
with	O
their	O
own	O
lens	B-Algorithm
mount	I-Algorithm
,	O
with	O
the	O
Four	B-Architecture
Thirds	I-Architecture
System	I-Architecture
being	O
a	O
partial	O
exception	O
.	O
</s>
<s>
This	O
was	O
different	O
before	O
1970	O
when	O
most	O
of	O
the	O
manufacturers	O
use	O
either	O
M42	B-Algorithm
or	O
M39	B-Algorithm
lenses	O
,	O
most	O
of	O
which	O
can	O
still	O
be	O
used	O
depending	O
on	O
the	O
particular	O
adapter	O
you	O
can	O
find	O
.	O
</s>
<s>
This	O
does	O
not	O
necessarily	O
mean	O
that	O
one	O
is	O
limited	O
to	O
only	O
mounting	O
,	O
for	O
example	O
,	O
Pentax	B-Application
lenses	O
on	O
a	O
Pentax	B-Application
camera	O
body	O
.	O
</s>
<s>
There	O
are	O
independent	O
optics	O
companies	O
that	O
make	O
lenses	O
for	O
the	O
various	O
otherwise	O
proprietary	O
mount	O
systems	O
,	O
thus	O
providing	O
alternative	O
sources	O
for	O
lenses	O
that	O
are	O
often	O
of	O
equal	O
quality	O
and/or	O
less	O
expensive	O
than	O
the	O
camera	O
maker	O
's	O
own	O
lenses	O
.	O
</s>
<s>
Another	O
possibility	O
is	O
the	O
use	O
of	O
adaptors	O
that	O
allow	O
mounting	O
a	O
lens	O
for	O
one	O
system	O
on	O
a	O
camera	O
with	O
a	O
different	O
lens	B-Algorithm
mount	I-Algorithm
.	O
</s>
<s>
However	O
,	O
the	O
use	O
of	O
an	O
adaptor	O
usually	O
results	O
in	O
reduced	O
functionality	O
,	O
typically	O
requiring	O
the	O
manual	O
setting	O
of	O
aperture	B-General_Concept
and	O
focus	O
,	O
or	O
perhaps	O
not	O
being	O
able	O
to	O
use	O
any	O
aperture	B-General_Concept
other	O
than	O
"	O
wide	O
open	O
"	O
.	O
</s>
<s>
The	O
M42	B-Algorithm
lens	I-Algorithm
mount	I-Algorithm
has	O
been	O
used	O
by	O
Leica	O
,	O
Nikon	B-Algorithm
,	O
Pentax	B-Application
,	O
Canon	O
,	O
Zenit	B-Application
,	O
Praktica	O
,	O
Fujica	B-Algorithm
,	O
Cosina	O
,	O
</s>
<s>
The	O
M42	B-Algorithm
lens	I-Algorithm
mount	I-Algorithm
is	O
a	O
screw	O
thread	O
mounting	O
standard	O
for	O
attaching	O
lenses	O
to	O
35	O
mm	O
cameras	O
,	O
primarily	O
single-lens	B-Algorithm
reflex	I-Algorithm
models	O
.	O
</s>
<s>
It	O
is	O
more	O
accurately	O
known	O
as	O
the	O
M42	B-Algorithm
×	O
1	O
mm	O
standard	O
,	O
which	O
means	O
that	O
it	O
is	O
a	O
metric	O
screw	O
thread	O
of	O
42	O
mm	O
diameter	O
and	O
1	O
mm	O
thread	O
pitch	O
.	O
</s>
<s>
(	O
The	O
M42	B-Algorithm
lens	I-Algorithm
mount	I-Algorithm
should	O
not	O
be	O
confused	O
with	O
the	O
T-mount	O
,	O
which	O
shares	O
the	O
42mm	O
throat	O
diameter	O
,	O
but	O
differs	O
by	O
having	O
a	O
0.75mm	O
thread	O
pitch	O
.	O
)	O
</s>
<s>
It	O
was	O
first	O
used	O
in	O
Zeiss	O
 '	O
Contax	O
S	B-Algorithm
of	O
1949	O
;	O
this	O
East	O
German	O
branch	O
of	O
Zeiss	O
also	O
sold	O
cameras	O
under	O
the	O
Pentacon	O
name	O
;	O
after	O
merger	O
with	O
other	O
East	O
German	O
photographic	O
manufacturers	O
,	O
the	O
name	O
Praktica	O
was	O
used	O
.	O
</s>
<s>
M42	B-Algorithm
thread	O
mount	O
cameras	O
first	O
became	O
well	O
known	O
under	O
the	O
Praktica	O
brand	O
,	O
and	O
thus	O
the	O
M42	B-Algorithm
mount	I-Algorithm
is	O
known	O
as	O
the	O
Praktica	B-Algorithm
thread	I-Algorithm
mount	I-Algorithm
.	O
</s>
<s>
 [ 1 ] 	O
Since	O
there	O
were	O
no	O
proprietary	O
elements	O
to	O
the	O
M42	B-Algorithm
mount	I-Algorithm
,	O
many	O
other	O
manufacturers	O
used	O
it	O
;	O
this	O
has	O
led	O
to	O
it	O
being	O
called	O
the	O
Universal	O
thread	O
mount	O
or	O
Universal	O
screw	O
mount	O
by	O
many	O
.	O
</s>
<s>
The	O
M42	B-Algorithm
mount	I-Algorithm
was	O
also	O
used	O
by	O
Pentax	B-Application
;	O
thus	O
,	O
it	O
is	O
also	O
known	O
as	O
the	O
Pentax	B-Application
thread	O
mount	O
,	O
despite	O
the	O
fact	O
that	O
Pentax	B-Application
did	O
not	O
originate	O
it	O
.	O
</s>
<s>
Canon	O
introduced	O
the	O
EF-lens	B-Application
mount	I-Application
in	O
1987	O
as	O
part	O
of	O
the	O
EOS	B-Algorithm
system	O
.	O
</s>
<s>
The	O
EF-S-mount	B-Algorithm
is	O
a	O
newer	O
subset	O
of	O
the	O
EF	O
standard	O
,	O
introduced	O
in	O
2003	O
.	O
</s>
<s>
EF-S	B-Algorithm
lenses	I-Algorithm
can	O
only	O
be	O
used	O
on	O
Canon	O
digital	O
cameras	O
that	O
use	O
the	O
APS-C	B-Algorithm
sensor	O
,	O
for	O
example	O
the	O
400D	B-Algorithm
(	O
EOS	B-Algorithm
Digital	I-Algorithm
Rebel	I-Algorithm
XTi	O
)	O
and	O
the	O
40D	B-Device
.	O
</s>
<s>
EF-S	B-Algorithm
lenses	I-Algorithm
can	O
be	O
distinguished	O
by	O
a	O
white	O
dot	O
on	O
the	O
mount	O
ring	O
,	O
as	O
opposed	O
to	O
the	O
red	O
dot	O
seen	O
on	O
standard	O
EF	B-Application
lenses	I-Application
.	O
</s>
<s>
Note	O
that	O
while	O
an	O
EF-S	B-Algorithm
lens	I-Algorithm
cannot	O
be	O
mounted	O
on	O
a	O
camera	O
that	O
uses	O
the	O
EF	B-Application
mount	I-Application
,	O
EF	B-Application
lenses	I-Application
can	O
be	O
mounted	O
on	O
cameras	O
designed	O
for	O
the	O
EF-S	B-Algorithm
standard	O
:	O
for	O
this	O
reason	O
,	O
EF-S	B-Algorithm
cameras	O
carry	O
both	O
a	O
red	O
dot	O
and	O
a	O
white	O
dot	O
on	O
the	O
mount	O
.	O
</s>
<s>
As	O
noted	O
above	O
under	O
focal	B-Algorithm
length	I-Algorithm
,	O
Canon	O
makes	O
DSLRs	B-Device
with	O
various	O
sensor	B-Algorithm
sizes	I-Algorithm
,	O
and	O
all	O
using	O
the	O
EF	O
or	O
EF-S	B-Algorithm
lens	I-Algorithm
mounts	O
.	O
</s>
<s>
This	O
leads	O
to	O
the	O
interesting	O
phenomenon	O
of	O
the	O
same	O
EF	B-Application
lens	I-Application
providing	O
different	O
angles	O
of	O
view	O
depending	O
on	O
which	O
camera	O
it	O
is	O
mounted	O
on	O
.	O
</s>
<s>
Third-party	O
lenses	O
compatible	O
with	O
Canon	O
's	O
EF	O
and	O
EF-S	B-Algorithm
mounts	I-Algorithm
are	O
manufactured	O
by	O
Sigma	O
,	O
Tamron	O
,	O
Tokina	O
and	O
Zeiss	O
.	O
</s>
<s>
The	O
manufacturers	O
of	O
these	O
lenses	O
have	O
reverse	O
engineered	O
the	O
electronics	O
of	O
the	O
EF	B-Application
lens	I-Application
mount	I-Application
.	O
</s>
<s>
The	O
Four	B-Architecture
Thirds	I-Architecture
System	I-Architecture
was	O
created	O
by	O
Olympus	O
and	O
Kodak	O
in	O
2001	O
,	O
and	O
is	O
designed	O
exclusively	O
for	O
digital	O
cameras	O
.	O
</s>
<s>
Currently	O
Olympus	O
,	O
Leica	O
(	O
in	O
cooperation	O
with	O
Panasonic	O
)	O
,	O
and	O
Sigma	O
are	O
making	O
lenses	O
under	O
Four	B-Architecture
Thirds	I-Architecture
System	I-Architecture
consortium	O
licensing	O
.	O
</s>
<s>
The	O
Four	B-Architecture
Thirds	I-Architecture
System	I-Architecture
sensor	B-Algorithm
size	I-Algorithm
(	O
17.3mm	O
x	B-Algorithm
13mm	O
)	O
is	O
the	O
smallest	O
currently	O
being	O
used	O
in	O
DSLR	B-Device
cameras	I-Device
.	O
</s>
<s>
There	O
are	O
currently	O
over	O
35	O
lenses	O
available	O
for	O
Four	B-Architecture
Thirds	I-Architecture
System	I-Architecture
cameras	O
.	O
</s>
<s>
A	O
complete	O
list	O
can	O
be	O
found	O
on	O
Andrzej	O
Wrotniak	O
's	O
web	O
site	O
.	O
</s>
<s>
Micro	B-Operating_System
Four	I-Operating_System
Thirds	I-Operating_System
is	O
a	O
variant	O
on	O
the	O
standard	O
Four	B-Architecture
Thirds	I-Architecture
system	I-Architecture
,	O
developed	O
by	O
Olympus	O
and	O
Panasonic	O
.	O
</s>
<s>
While	O
these	O
cameras	O
are	O
technically	O
not	O
DSLRs	B-Device
,	O
they	O
are	O
similar	O
in	O
operation	O
,	O
and	O
use	O
similar	O
interchangeable	O
lenses	O
.	O
</s>
<s>
The	O
Micro	B-Operating_System
Four	I-Operating_System
Thirds	I-Operating_System
lens	B-Algorithm
mount	I-Algorithm
is	O
a	O
slightly	O
modified	O
version	O
of	O
the	O
standard	O
Four	B-Architecture
Thirds	I-Architecture
mount	O
,	O
and	O
a	O
number	O
of	O
lenses	O
have	O
been	O
built	O
for	O
it	O
.	O
</s>
<s>
Because	O
the	O
lack	O
of	O
a	O
mirror	O
,	O
optical	O
viewfinder	O
,	O
and	O
a	O
shorter	O
flange-focal	O
distance	O
these	O
lenses	O
can	O
be	O
more	O
compact	O
than	O
those	O
for	O
standard	O
Four	B-Architecture
Thirds	I-Architecture
.	O
</s>
<s>
Standard	O
Four	B-Architecture
Thirds	I-Architecture
lenses	O
can	O
be	O
used	O
on	O
a	O
Micro	B-Operating_System
Four	I-Operating_System
Thirds	I-Operating_System
camera	O
with	O
full	O
electronic	O
communication	O
using	O
an	O
adapter	O
,	O
but	O
those	O
that	O
do	O
not	O
support	O
contrast-detect	O
autofocus	O
will	O
only	O
autofocus	O
slowly	O
,	O
if	O
at	O
all	O
.	O
</s>
<s>
Micro	B-Operating_System
Four	I-Operating_System
Thirds	I-Operating_System
lenses	O
can	O
not	O
be	O
used	O
on	O
a	O
standard	O
Four	B-Architecture
Thirds	I-Architecture
camera	O
.	O
</s>
<s>
The	O
Minolta	B-Application
A-mount	I-Application
system	I-Application
was	O
introduced	O
with	O
the	O
Minolta	B-Algorithm
Maxxum	I-Algorithm
7000	I-Algorithm
camera	O
in	O
1985	O
,	O
along	O
with	O
11	O
AF-mount	O
lenses	O
.	O
</s>
<s>
In	O
North	O
America	O
,	O
Minolta	O
began	O
using	O
the	O
name	O
'	O
Maxxum	B-Application
 '	O
for	O
the	O
SLR	B-Algorithm
autofocus	O
cameras	O
,	O
lenses	O
and	O
flashes	O
while	O
in	O
Europe	O
they	O
were	O
called	O
'	O
AF	O
 '	O
(	O
first	O
series	O
)	O
and	O
'	O
Dynax	B-Application
 '	O
(	O
second	O
and	O
later	O
generations	O
)	O
,	O
and	O
in	O
Asia	O
the	O
'	O
α	O
 '	O
(	O
Alpha	O
)	O
branding	O
was	O
used	O
,	O
though	O
they	O
were	O
otherwise	O
identical	O
in	O
appearance	O
and	O
function	O
-	O
all	O
of	O
the	O
equipment	O
is	O
100%	O
interchangeable	O
regardless	O
which	O
of	O
the	O
names	O
it	O
carries	O
.	O
</s>
<s>
Most	O
Minolta	B-Application
A-mount	I-Application
compatible	O
lenses	O
,	O
whether	O
built	O
by	O
Minolta	O
or	O
one	O
of	O
the	O
aftermarket	O
lens	O
manufacturers	O
,	O
are	O
focused	O
externally	O
by	O
a	O
shaft	O
connecting	O
the	O
autofocus	O
computer	O
and	O
motor	O
inside	O
the	O
camera	O
body	O
that	O
mechanically	O
connects	O
to	O
the	O
internal	O
focusing	O
gears	O
inside	O
of	O
the	O
lens	O
body	O
.	O
</s>
<s>
A	O
couple	O
of	O
later	O
Minolta	O
lenses	O
do	O
have	O
a	O
built-in	O
ultrasonic	O
focus	O
motor	O
(	O
SSM	O
lenses	O
)	O
,	O
like	O
other	O
SLR	B-Algorithm
and	O
DSLR	B-Device
systems	O
(	O
i.e.	O
</s>
<s>
Canon	O
and	O
Nikon	B-Algorithm
)	O
,	O
where	O
the	O
AF	O
computer	O
is	O
inside	O
the	O
camera	O
body	O
and	O
there	O
is	O
a	O
digital	O
interface	O
connecting	O
body	O
to	O
an	O
electric	O
motor	O
and	O
the	O
focusing	O
gears	O
built	O
into	O
the	O
lens	O
body	O
.	O
</s>
<s>
Konica	O
Minolta	O
sold	O
the	O
rights	O
to	O
their	O
Minolta	B-Application
AF	I-Application
lens	I-Application
mount	I-Application
to	O
Sony	O
in	O
2006	O
.	O
</s>
<s>
Sony	O
acquired	O
Konica	O
Minolta	O
's	O
camera	O
technologies	O
in	O
2006	O
,	O
and	O
chose	O
the	O
"	O
α	O
"	O
brand	O
name	O
,	O
already	O
in	O
use	O
by	O
Minolta	O
in	O
Asia	O
,	O
for	O
their	O
new	O
"	O
Sony	B-Algorithm
α	I-Algorithm
"	O
digital	B-Device
SLR	I-Device
system	O
.	O
</s>
<s>
The	O
company	O
has	O
since	O
abandoned	O
traditional	O
SLR	B-Algorithm
design	O
,	O
and	O
now	O
uses	O
the	O
"	O
α	O
"	O
brand	O
name	O
for	O
its	O
current	O
line	O
of	O
SLT	B-Device
and	I-Device
ILCA	I-Device
cameras	O
with	O
fixed	O
semi-reflective	O
mirrors	O
and	O
electronic	O
viewfinders	O
,	O
as	O
well	O
as	O
its	O
current	O
line	O
of	O
E-mount	B-Algorithm
mirrorless	B-Device
cameras	I-Device
.	O
</s>
<s>
The	O
Minolta	B-Application
A-mount	I-Application
was	O
retained	O
from	O
the	O
old	O
cameras	O
and	O
was	O
originally	O
named	O
the	O
"	O
Sony	B-Algorithm
α	I-Algorithm
mount	I-Algorithm
system	I-Algorithm
"	O
.	O
</s>
<s>
Sony	O
has	O
produced	O
several	O
new	O
lenses	O
for	O
its	O
A-mount	O
,	O
and	O
the	O
current	O
list	O
of	O
Minolta	O
and	O
Sony	B-Algorithm
A-mount	I-Algorithm
lenses	O
has	O
over	O
60	O
entries	O
.	O
</s>
<s>
Some	O
of	O
the	O
newest	O
A-mount	O
lenses	O
are	O
designated	O
"	O
DT	O
"	O
for	O
Digital	O
Technology	O
;	O
these	O
are	O
for	O
digital	O
cameras	O
with	O
APS-C	B-Algorithm
sensors	O
,	O
and	O
will	O
result	O
in	O
vignetting	O
if	O
used	O
on	O
a	O
film	O
SLR	B-Algorithm
or	O
a	O
full	B-Algorithm
frame	I-Algorithm
DSLR	I-Algorithm
or	O
full	O
frame	O
SLT	O
camera	O
.	O
</s>
<s>
Third-party	O
lenses	O
for	O
the	O
AF	O
lens	B-Algorithm
mount	I-Algorithm
are	O
made	O
by	O
Zeiss	O
,	O
Sigma	O
,	O
Tamron	O
,	O
Tokina	O
and	O
Vivitar	O
.	O
</s>
<s>
The	O
Nikon	B-Architecture
F-mount	I-Architecture
was	O
introduced	O
by	O
Nikon	B-Algorithm
in	O
1959	O
,	O
and	O
is	O
thus	O
one	O
of	O
the	O
most	O
venerable	O
lens	B-Algorithm
mounts	I-Algorithm
still	O
in	O
existence	O
.	O
</s>
<s>
Another	O
factor	O
that	O
makes	O
the	O
Nikon	B-Architecture
F-mount	I-Architecture
popular	O
is	O
that	O
several	O
other	O
camera	O
manufacturers	O
,	O
for	O
example	O
Fujifilm	O
,	O
have	O
adopted	O
it	O
.	O
</s>
<s>
F-mount	B-Architecture
photographic	O
lenses	O
are	O
currently	O
made	O
by	O
Nikon	B-Algorithm
,	O
Zeiss	O
,	O
Voigtländer	O
,	O
Schneider	O
,	O
Sigma	O
,	O
Tokina	O
,	O
Tamron	O
,	O
Hartblei	O
,	O
Kiev-Arsenal	B-Algorithm
,	O
Lensbaby	O
,	O
Vivitar	O
,	O
and	O
others	O
,	O
and	O
over	O
400	O
lenses	O
are	O
compatible	O
with	O
the	O
system	O
.	O
</s>
<s>
Most	O
Nikon	B-Architecture
F-mount	I-Architecture
lenses	O
cover	O
the	O
standard	O
36×24mm	O
area	O
of	O
135	O
film	O
,	O
while	O
"	O
DX	O
"	O
designated	O
lenses	O
cover	O
the	O
24×16mm	O
area	O
of	O
the	O
Nikon	B-Algorithm
DX	O
format	O
DSLR	B-Device
sensors	O
,	O
commonly	O
referred	O
to	O
as	O
APS-C	B-Algorithm
format	I-Algorithm
.	O
</s>
<s>
While	O
"	O
DX	O
"	O
lenses	O
can	O
be	O
physically	O
mounted	O
on	O
any	O
Nikon	B-Algorithm
film	O
or	O
digital	B-Device
SLR	I-Device
that	O
support	O
the	O
"	O
AI	O
"	O
exposure	O
indexing	O
feature	O
(	O
produced	O
from	O
1977	O
)	O
,	O
there	O
will	O
be	O
some	O
degree	O
of	O
vignetting	O
when	O
used	O
on	O
film	O
cameras	O
,	O
depending	O
on	O
zoom	O
setting	O
.	O
</s>
<s>
All	O
Nikon	B-Algorithm
full-frame	B-Algorithm
"	O
FX	O
"	O
DSLRs	B-Device
have	O
a	O
DX-compatible	O
mode	O
that	O
,	O
by	O
default	O
when	O
a	O
DX-format	O
lens	O
is	O
attached	O
,	O
crops	O
the	O
captured	O
frames	O
to	O
the	O
DX	O
format	O
and	O
adjusts	O
the	O
viewfinder	O
to	O
reflect	O
the	O
smaller	O
capture	O
area	O
.	O
</s>
<s>
There	O
are	O
basically	O
three	O
types	O
of	O
F	B-Architecture
mount	I-Architecture
Nikon	B-Algorithm
lens	O
:	O
</s>
<s>
Industrial	O
F-mount	B-Architecture
lenses	O
have	O
varying	O
,	O
often	O
small	O
,	O
film/sensor	O
coverage	O
.	O
</s>
<s>
Older	O
F-mount	B-Architecture
lenses	O
designed	O
for	O
film	O
cameras	O
will	O
work	O
on	O
modern	O
SLR	B-Algorithm
or	O
DSLR	B-Device
cameras	I-Device
with	O
some	O
limitations	O
,	O
typically	O
not	O
providing	O
autofocus	O
or	O
automatic	O
aperture	B-General_Concept
setting	O
.	O
</s>
<s>
Entry	O
level	O
Nikon	B-Algorithm
DSLRs	B-Device
such	O
as	O
Nikon	B-Algorithm
D40	I-Algorithm
,	O
D40X	B-Algorithm
,	O
D60	B-Algorithm
,	O
D3000	B-Algorithm
,	O
D3100	B-Algorithm
,	O
D5000	B-Algorithm
and	O
D5100	B-Algorithm
do	O
not	O
have	O
an	O
integrated	O
focus	O
motor	O
,	O
so	O
they	O
will	O
not	O
autofocus	O
with	O
AF	O
&	O
AF-D	O
lenses	O
.	O
</s>
<s>
Similarly	O
,	O
some	O
AF-I	O
&	O
AF-S	O
lenses	O
will	O
not	O
work	O
on	O
some	O
older	O
Nikon	B-Algorithm
AF	O
film	O
SLRs	B-Algorithm
.	O
</s>
<s>
The	O
Nikon	B-Algorithm
1-mount	I-Algorithm
was	O
announced	O
on	O
21	O
September	O
2011	O
together	O
with	O
the	O
Nikon	B-Algorithm
1	I-Algorithm
series	I-Algorithm
high-speed	O
mirrorless	B-Device
interchangeable-lens	I-Device
cameras	I-Device
.	O
</s>
<s>
The	O
Pentax	B-Algorithm
K-mount	I-Algorithm
(	O
or	O
just	O
"	O
PK	O
mount	O
"	O
)	O
was	O
created	O
by	O
Pentax	B-Application
in	O
1975	O
,	O
and	O
has	O
been	O
used	O
by	O
all	O
Pentax	B-Application
35mm	O
and	O
digital	B-Device
SLRs	I-Device
since	O
.	O
</s>
<s>
For	O
more	O
information	O
see	O
the	O
Pentax	B-Algorithm
K	I-Algorithm
mount	I-Algorithm
article	O
or	O
Bojidar	O
Dimitrov	O
's	O
web	O
site	O
.	O
</s>
<s>
A	O
number	O
of	O
other	O
manufacturers	O
have	O
produced	O
K-mount	B-Algorithm
lenses	O
,	O
and	O
several	O
other	O
manufacturers	O
(	O
such	O
as	O
Konica	O
and	O
Ricoh	O
)	O
have	O
made	O
K-mount	B-Algorithm
cameras	O
.	O
</s>
<s>
In	O
2005	O
Pentax	B-Application
and	O
Samsung	O
entered	O
into	O
a	O
cooperation	O
resulting	O
in	O
the	O
Samsung	O
GX	O
line	O
of	O
DSLRs	B-Device
,	O
based	O
largely	O
on	O
Pentax	B-Application
technology	O
including	O
the	O
Pentax	B-Algorithm
K	I-Algorithm
mount	I-Algorithm
.	O
</s>
<s>
Sigma	O
Corporation	O
,	O
better	O
known	O
for	O
manufacturing	O
lenses	O
for	O
other	O
cameras	O
,	O
has	O
made	O
some	O
film	O
SLR	B-Algorithm
and	O
DSLR	B-Device
cameras	I-Device
themselves	O
.	O
</s>
<s>
These	O
cameras	O
use	O
the	O
Sigma	B-Algorithm
SA-mount	I-Algorithm
,	O
for	O
which	O
Sigma	O
makes	O
a	O
line	O
of	O
lenses	O
.	O
</s>
<s>
The	O
Sigma	O
DSLR	B-Device
cameras	I-Device
that	O
use	O
the	O
SA	B-Algorithm
mount	I-Algorithm
are	O
the	O
Sigma	B-Algorithm
SD9	I-Algorithm
,	O
SD10	B-Algorithm
,	O
SD14	B-Algorithm
,	O
SD15	B-Algorithm
and	O
SD1	B-Device
Merrill	I-Device
.	O
</s>
<s>
These	O
cameras	O
are	O
noteworthy	O
for	O
their	O
use	O
of	O
the	O
Foveon	B-Algorithm
X3	I-Algorithm
sensor	I-Algorithm
,	O
an	O
image	B-Algorithm
sensor	I-Algorithm
that	O
works	O
on	O
quite	O
different	O
principles	O
from	O
the	O
sensors	O
used	O
in	O
all	O
other	O
digital	O
cameras	O
.	O
</s>
<s>
The	O
Nikon	B-Architecture
F-mount	I-Architecture
lens	O
systems	O
and	O
the	O
Pentax	B-Algorithm
K-mount	I-Algorithm
systems	O
are	O
the	O
only	O
35mm	O
SLR	B-Algorithm
camera	I-Algorithm
systems	O
(	O
apart	O
from	O
the	O
Leica	O
M-mount	O
rangefinder	O
system	O
)	O
that	O
allow	O
a	O
photographer	O
to	O
use	O
a	O
mechanical	O
SLR	B-Algorithm
camera	I-Algorithm
body	O
,	O
a	O
fully	O
automatic	O
SLR	B-Algorithm
camera	I-Algorithm
body	O
,	O
and	O
a	O
DSLR	B-Device
camera	I-Device
body	O
,	O
all	O
utilizing	O
the	O
same	O
lenses	O
.	O
</s>
<s>
The	O
only	O
aspects	O
of	O
these	O
manufacturers	O
 '	O
lenses	O
that	O
have	O
changed	O
are	O
the	O
addition	O
of	O
electronic	O
contacts	O
,	O
autofocus	O
abilities	O
and	O
,	O
in	O
some	O
cases	O
,	O
the	O
elimination	O
of	O
the	O
external	O
aperture	B-General_Concept
ring	O
for	O
electronic	O
control	O
(	O
i.e.	O
,	O
Nikon	B-Algorithm
's	O
'	O
G-type	O
'	O
auto-Nikkors	O
,	O
which	O
cannot	O
be	O
used	O
on	O
a	O
mechanical	O
SLR	B-Algorithm
camera	I-Algorithm
body	O
)	O
.	O
</s>
<s>
Canon	O
,	O
Minolta	O
(	O
Sony	O
)	O
,	O
Olympus	O
,	O
and	O
other	O
manufacturers	O
have	O
changed	O
lens	B-Algorithm
mounts	I-Algorithm
.	O
</s>
<s>
Much	O
older	O
Canon	O
film	O
cameras	O
used	O
the	O
FD	B-Algorithm
lens	I-Algorithm
mount	I-Algorithm
,	O
which	O
was	O
discontinued	O
in	O
1987	O
in	O
favor	O
of	O
the	O
EF	B-Application
lens	I-Application
mount	I-Application
.	O
</s>
<s>
Olympus	O
discontinued	O
the	O
OM	O
lens	B-Algorithm
mount	I-Algorithm
for	O
the	O
OM	O
series	O
cameras	O
in	O
favor	O
of	O
the	O
Four	B-Architecture
Thirds	I-Architecture
System	I-Architecture
lens	B-Algorithm
mount	I-Algorithm
.	O
</s>
<s>
However	O
,	O
due	O
to	O
the	O
size	O
of	O
the	O
Four	B-Architecture
Thirds	I-Architecture
mount	O
it	O
is	O
possible	O
to	O
fit	O
legacy	O
SLR	B-Algorithm
lenses	O
from	O
any	O
manufacturer	O
using	O
an	O
adapter	O
,	O
albeit	O
with	O
manual	O
aperture	B-General_Concept
and	O
focus	O
control	O
.	O
</s>
<s>
All	O
Minolta	B-Application
A-mount	I-Application
lenses	O
work	O
on	O
compatible	O
Minolta	O
SLR	B-Algorithm
film	O
bodies	O
and	O
on	O
Sony	B-Algorithm
A-mount	I-Algorithm
DSLR	B-Device
and	O
SLT	O
bodies	O
.	O
</s>
