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 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:
In photography, bokeh is the aesthetic quality of the blur produced in out-of-focus parts of an image, caused by circles of confusion. Bokeh has also been defined as "the way the lens renders out-of-focus points of light". Differences in lens aberrations and aperture shape cause very different bokeh effects. Some lens designs blur the image in a way that is pleasing to the eye, while others produce distracting or unpleasant blurring. Photographers may deliberately use a shallow focus technique to create images with prominent out-of-focus regions, accentuating their lens's bokeh.
Carl Zeiss AG, branded as ZEISS, is a German manufacturer of optical systems and optoelectronics, founded in Jena, Germany in 1846 by optician Carl Zeiss. Together with Ernst Abbe and Otto Schott he laid the foundation for today's multinational company. The current company emerged from a reunification of Carl Zeiss companies in East and West Germany with a consolidation phase in the 1990s. ZEISS is active in four business segments with approximately equal revenue in almost 50 countries, has 30 production sites and around 25 development sites worldwide.
In photography, bracketing is the general technique of taking several shots of the same subject using different camera settings, typically with the aim of combining the images in postprocessing. Bracketing is useful and often recommended in situations that make it difficult to obtain a satisfactory image with a single shot, especially when a small variation in exposure parameters has a comparatively large effect on the resulting image. Given the time it takes to accomplish multiple shots, it is typically, but not always, used for static subjects. Autobracketing is a feature of many modern cameras. When set, it will automatically take several bracketed shots, rather than the photographer altering the settings by hand between each shot.
Jos. Schneider Optische Werke GmbH is a manufacturer of industrial and photographic optics. The company was founded on 18 January 1913 by Joseph Schneider as Optische Anstalt Jos. Schneider & Co. at Bad Kreuznach in Germany. The company changed its name to Jos. Schneider & Co., Optische Werke, Kreuznach in 1922, and to the current Jos. Schneider Optische Werke GmbH in 1998.
Vivitar Corporation is a manufacturer, distributor, and marketer of photographic and optical equipment originally based in Santa Monica, California. Since 2008, the Vivitar name serves as Sakar International's house brand for digital imaging, optics, mobile accessories, and audio products.
In signal processing, apodization 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 primarily used to remove Airy disks caused by diffraction around an intensity peak, improving the focus.
The Pentax K-mount, sometimes referred to as the "PK-mount", is a bayonet lens mount standard for mounting interchangeable photographic lenses to 35 mm single-lens reflex (SLR) cameras. It was created by Pentax in 1975, and has since been used by all Pentax 35 mm and digital SLRs and also the MILC Pentax K-01. A number of other manufacturers have also produced many K-mount lenses and K-mount cameras.
Image stabilization (IS) is a family of techniques that reduce blurring associated with the motion of a camera or other imaging device during exposure.
Originally produced by Minolta, and currently produced by Sony, the STF 135mm f/2.8 [T4.5] is a photographic lens compatible with cameras using the Minolta AF and Sony α A-mount. STF stands for Smooth Trans Focus, in reference to its special optical system, which is intended to smooth the transition between the plane of focus and out-of-focus areas in the image. This is accomplished by the use of an apodization filter that provides the high-quality bokeh effect. The lens is not a soft-focus lens.
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-mount, with a flange focal distance 44.50 mm, one millimeter longer, 43.5 mm, than the previous SR mount from 1958. The new mount was wider, 49.7 mm vs. 44.97 mm, than the older SR-mount and due to the longer flange focal distance, old manual lenses were incompatible with the new system. Minolta bought the autofocus technology of Leica Correfot camera which was partly used on the a-mount autofocus technology. The mount is now used by Sony, who bought the SLR camera division from Konica Minolta, Konica and Minolta having merged a few years before.
The Fujifilm X-mount is a lens mount for Fujifilm interchangeable lens mirrorless cameras in its X-series, designed for 23.6mm x 15.6mm APS-C sensors.
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.
The Sony FE 90mm F2.8 Macro G OSS is a full-frame macro prime lens for the Sony E-mount, announced by Sony on 4 March 2015.
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 Venus Optics Laowa 105mm F2 Smooth Trans Focus lens is a smooth trans focus full-frame prime lens for Canon EF, Nikon AI, Sony A, Sony E, and Pentax K mounts, announced by Venus Optics in September 2016. It is marketed as the "Bokeh Dreamer" lens.
The Zeiss Batis Sonnar T* 2.8/135mm is a full-frame (FE) telephoto prime lens for the Sony E-mount, announced by Zeiss on April 24, 2017.
The Canon RF lens mount is an interchangeable-lens mount developed by Canon for its full-frame mirrorless interchangeable-lens cameras, and featured first by the EOS R, followed by the EOS RP. The RF mount was announced in September 2018. In May 2022, Canon announced APS-C EOS R cameras and RF-S lenses designed for these cameras.