Smooth Trans Focus

The Smooth Trans Focus (STF) technology in <a href="/facts/Photographic_lens/TkL6sd1b">photographic lenses</a> uses an <a href="/facts/Apodization_filter/Tc0rMnuV">apodization filter</a> to realize notably smooth <a href="/facts/Bokeh/BahN1Q2R">bokeh</a> 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 <a href="/facts/Minolta/7Fxhx5df">Minolta</a> in the 1980s, and first implemented in a commercially available lens in 1999. In contrast to <a href="/facts/Soft_focus/ISj6c9E0">soft focus lenses</a>, STF lenses render a perfectly sharp image in the focus plane.
Lenses featuring Smooth Trans Focus technology:

<ul><li><a href="/facts/Minolta_STF_135mm_F2.8_T4.5/9MvhB6yQ">Minolta STF 135mm F2.8 [T4.5]</a> (introduced 1999)</li>
<li><a href="/facts/Sony_%CE%B1_STF_135mm_F2.8_T4.5/9MvhB6yQ">Sony α STF 135mm F2.8 [T4.5]</a> (SAL-135F28) (introduced 2006)</li>
<li><a href="/facts/Sony_FE_100mm_F2.8_STF_GM_OSS/WL6LSsuz">Sony FE 100mm F2.8 STF GM OSS</a> (<a href="/facts/SEL-100F28GM/LKqMC6US">SEL-100F28GM</a>) (introduced 2017)</li></ul>

Smooth Trans Focus open-in-new

Smooth Trans Focus