The Smooth Trans Focus (STF) technology in
photographic lens
A camera lens (also known as photographic lens or photographic objective) is an optical lens or assembly of lenses used in conjunction with a camera body and mechanism to make images of objects either on photographic film or on other media capa ...
es uses an
apodization filter to realize notably smooth
bokeh
In photography, bokeh ( or ; ) is the aesthetic quality of the blur produced in out-of-focus parts of an image. Bokeh has also been defined as "the way the lens renders out-of-focus points of light". Differences in lens aberrations and ...
with rounded out-of-focus highlights in both the foreground and background. This is accomplished by utilizing a concave neutral-gray tinted lens element next to the aperture blades as apodization filter, a technology originally invented (and patented) by
Minolta
was a Japanese manufacturer of cameras, camera accessories, photocopiers, fax machines, and laser printers. Minolta Co., Ltd., which is also known simply as Minolta, was founded in Osaka, Japan, in 1928 as . It made the first integrated autofocu ...
in the 1980s, and first implemented in a commercially available lens in 1999. In contrast to
soft focus lenses, STF lenses render a perfectly sharp image in the focus plane.
Lenses featuring ''Smooth Trans Focus'' technology:
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Minolta STF 135mm F2.8 4.5(introduced 1999)
*
Sony α STF 135mm F2.8 4.5(SAL-135F28) (introduced 2006)
*
Sony FE 100mm F2.8 STF GM OSS
The Sony FE 100mm F2.8 STF GM OSS is a premium full-frame smooth trans focus prime lens for the Sony E-mount, announced by Sony in 2017.
The lens is currently Sony's only native lens offering Smooth Trans Focus. This compromise in design results ...
(
SEL-100F28GM) (introduced 2017)
See also
*
STF function (an emulation of the effect in the
Minolta Maxxum 7)
*
Fujinon XF 56mm F1.2 R APD
The Fujinon XF 56mm F1.2 R is an interchangeable camera lens announced by Fujifilm on January 6, 2014. As of 2015, it is one of the widest-aperture native mirrorless lenses.
APD variant
In September 2014, Fujifilm announced a variant of this lens, ...
(a similar lens introduced by
Fujifilm
, trading as Fujifilm, or simply Fuji, is a Japanese multinational conglomerate headquartered in Tokyo, Japan, operating in the realms of photography, optics, office and medical electronics, biotechnology, and chemicals.
The offerings from ...
in 2014)
*
Venus Optics Laowa 105mm f/2 Smooth Trans Focus (a similar lens introduced by Venus Optics in 2016)
*
f-stop
*
T-stop
References
Minolta A-mount lenses
Sony A-mount lenses
Sony E-mount lenses
Photographic lenses by type
Photographic lens designs
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