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 capab ...
es uses an
apodization filter
In signal processing, apodization (from Greek "removing the foot") is the modification of the shape of a mathematical function. The function may represent an electrical signal, an optical transmission or a mechanical structure. In optics, it is ...
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:
*
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 (
SEL-100F28GM
Sony released the following ''SEL'' (for: ''S''ony ''E''-mount ''L''ens) lenses for Sony E-mount cameras since 2010. They are also compatible with Hasselblad E-mount cameras. Some of the lenses introduced into the line have been developed in coope ...
) (introduced 2017)
See also
*
STF function
Autobracketing is a feature of some more advanced cameras, whether film or digital cameras, particularly single-lens reflex cameras, where the camera will take several successive shots (often three) with slightly different settings. The images may ...
(an emulation of the effect in the
Minolta Maxxum 7
The Minolta A-mount camera system was a line of photographic equipment from Minolta introduced in 1985 with the world's first integrated autofocus system in the camera body with interchangeable lenses. The system used a lens mount called A-moun ...
)
*
Fujinon XF 56mm F1.2 R APD (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 th ...
in 2014)
*
Venus Optics
Venus Optics (Anhui ChangGeng Optics Technology Co., Ltd.) is a Chinese manufacturer of photographic lenses, specialized in the design of innovative macro, wide angle, shift and f/0.95 lenses. Headquarters and production are in Hefei, while ...
Laowa 105mm f/2 Smooth Trans Focus (a similar lens introduced by Venus Optics in 2016)
*
f-stop
In optics, the f-number of an optical system such as a camera lens is the ratio of the system's focal length to the diameter of the entrance pupil ("clear aperture").Smith, Warren ''Modern Optical Engineering'', 4th Ed., 2007 McGraw-Hill ...
*
T-stop
In optics, the f-number of an optical system such as a camera lens is the ratio of the system's focal length to the diameter of the entrance pupil ("clear aperture").Smith, Warren ''Modern Optical Engineering'', 4th Ed., 2007 McGraw-Hill ...
References
Minolta A-mount lenses
Sony A-mount lenses
Sony E-mount lenses
Photographic lenses by type
Photographic lens designs
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