The Smooth Trans Focus (STF) technology in
photographic lens
A camera lens, photographic lens or photographic objective is an optical lens (optics), lens or assembly of lenses (compound lens) used in conjunction with a camera body and mechanism to Imaging, make images of objects either on photographic film ...
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, whether foreground or background or both. It is created by using a wide aperture lens.
Some photographers incorrectly restr ...
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, lenses, 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 ...
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) (introduced 2017)
See also
*
STF function (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-mo ...
)
*
Fujinon XF 56mm F1.2 R APD (a similar lens introduced by
Fujifilm
, trading as , or simply Fuji, is a Japanese Multinational corporation, multinational Conglomerate (company), conglomerate headquartered in Tokyo, Japan, operating in the areas of photography, optics, Office supplies, office and Biomedical engine ...
in 2014)
*
Venus Optics Laowa 105mm f/2 Smooth Trans Focus (a similar lens introduced by Venus Optics in 2016)
*
f-stop
An f-number is a measure of the light-gathering ability of an optical system such as a camera lens. It is calculated by dividing the system's focal length by the diameter of the entrance pupil ("clear aperture").Smith, Warren ''Modern Optical ...
*
T-stop
References
Minolta A-mount lenses
Sony A-mount lenses
Sony E-mount lenses
Photographic lens designs
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