<s>
Originally	O
produced	O
by	O
Minolta	O
,	O
and	O
currently	O
produced	O
by	O
Sony	O
,	O
the	O
STF	O
135mm	O
f/2.8	O
 [ T4.5 ] 	O
is	O
a	O
photographic	O
lens	O
compatible	O
with	O
cameras	O
using	O
the	O
Minolta	B-Application
AF	I-Application
and	O
Sony	B-Algorithm
α	I-Algorithm
A-mount	B-Algorithm
.	O
</s>
<s>
This	O
is	O
accomplished	O
by	O
the	O
use	O
of	O
an	O
apodization	B-Algorithm
filter	I-Algorithm
that	O
provides	O
the	O
high-quality	O
bokeh	O
effect	O
.	O
</s>
<s>
Apodization	B-Algorithm
is	O
a	O
process	O
in	O
spatial	O
signal	O
processing	O
which	O
can	O
enhance	O
resolution	O
by	O
reducing	O
the	O
secondary	O
maxima	O
in	O
the	O
diffraction	O
pattern	O
of	O
the	O
lens	O
 '	O
aperture	O
.	O
</s>
<s>
The	O
STF	O
lens	O
features	O
an	O
optical	O
apodization	B-Algorithm
filter	I-Algorithm
in	O
form	O
of	O
a	O
neutral-gray	O
tinted	O
concave	O
lens	O
element	O
near	O
the	O
lens	O
 '	O
diaphragm	O
modulating	O
the	O
intensity	O
profiles	O
of	O
the	O
circles	O
of	O
confusion	O
in	O
such	O
a	O
way	O
as	O
to	O
become	O
truly	O
Gaussian	B-Application
.	O
</s>
<s>
The	O
optical	O
effect	O
can	O
be	O
emulated	O
by	O
combining	O
depth-of-field	O
bracketing	O
with	O
multi	O
exposure	O
,	O
as	O
implemented	O
in	O
the	O
Minolta	B-Algorithm
Maxxum	I-Algorithm
7	I-Algorithm
's	O
STF	O
function	O
.	O
</s>
<s>
In	O
2014	O
,	O
Fujifilm	O
announced	O
a	O
lens	O
utilizing	O
a	O
similar	O
apodization	B-Algorithm
filter	I-Algorithm
in	O
the	O
Fujinon	O
XF	O
56mm	O
F1.2	O
R	O
APD	O
lens	O
.	O
</s>
<s>
In	O
2017	O
,	O
Sony	O
added	O
the	O
Sony	B-Algorithm
FE	I-Algorithm
100mm	I-Algorithm
F2.8	I-Algorithm
STF	I-Algorithm
GM	I-Algorithm
OSS	I-Algorithm
(	O
SEL-100F28GM	O
)	O
for	O
E-mount	B-Algorithm
cameras	O
.	O
</s>
