The Smooth Trans Focus (STF) technology in
photographic lenses uses an
apodization filter to realize notably smooth
bokeh 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 aut ...
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)
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Sony α STF 135mm F2.8 4.5(SAL-135F28) (introduced 2006)
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Sony FE 100mm F2.8 STF GM OSS (
SEL-100F28GM) (introduced 2017)
See also
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STF function (an emulation of the effect in the
Minolta Maxxum 7)
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Fujinon XF 56mm F1.2 R APD (a similar lens introduced by
Fujifilm 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 s ...
Laowa 105mm f/2 Smooth Trans Focus (a similar lens introduced by Venus Optics in 2016)
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f-stop
*
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 Pro ...
References
Minolta A-mount lenses
Sony A-mount lenses
Sony E-mount lenses
Photographic lenses by type
Photographic lens designs
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