There are many reasons to ignore the Sony FE 100mm F2.8 STF GM OSS Lens. It could be that it’s not practical. It’s slow. It’s pricey. It has a lo-o-o-ong name. Despite these potential pitfalls, the 100mm leverages a unique optical design to deliver breathtaking bokeh and outstanding sharpness. This performance has made the 100mm STF one of the most used lenses in my kit.
What makes this 100mm special is its use of Smooth Trans Focus, or apodization, optics. In layperson’s terms, this means the lens will produce incredibly smooth, round bokeh, at the cost of light-gathering capabilities. For those more interested in the technical aspects, the apodization element is essentially a radial graduated neutral density filter that smooths and rounds out the rough edges of the bokeh it renders.
Unfortunately, no good deed goes unpunished. The special element results in light loss, and explains the use of T (transmission) numbers on the lens barrel. Nominally, the lens is an f/2.8. This determines all sorts of lens properties, namely, depth of field and light gathering. With that extra STF element in there, this f/2.8 is transformed into a T5.6 lens. The depth of field is not dramatically affected, so the 100mm STF is going to look like an f/2.8 lens, though for exposure purposes, it is functionally an f/5.6.
Surprisingly, this light loss has made it even more viable for my work because I can use it to shoot video in brighter light without requiring a ND filter and without giving up shallow depth of field. It also just makes things look good. Smooth bokeh is never a bad thing, and not needing another piece of kit in my bag when I want to switch from stills to video is a huge benefit. It’s also relatively lightweight and has a physical de-clickable aperture ring for even better control in video.
One more feature has secured its place in my bag: a maximum magnification ratio of 1:2. I generally like to keep a macro around, and this lens fulfills that purpose. Rarely do I need 1:1, but just being able to get a bit closer is a very useful function. It’s also tack sharp, even in macro mode, making it a spectacular lens for a wide range of applications, be it portraits, product shots, and even food photography. I can appreciate one lens that can take care of so many things and do them all well.
Have you experimented with apodization or Smooth Trans Focus lenses before? Have you been thinking about picking one up or wondering exactly what that means? Make sure to tell us what you think in the Comments section, below!
The “Things We Love” series articles are written by B&H Photo Video Pro Audio staff to talk about products and items that we love. Opinions expressed in the articles are those of the writers and do not represent product endorsements from B&H Photo Video Pro Audio.