Laowa 105mm f/2 STF - Review / Lens Test
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Review by Klaus Schroiff, published June 2016
Startup lens manufacturers face a rather difficult business environment these days. The market is not only crowded but it's also shrinking. Competing on the same grounds with the more established players is a hopeless or at least tiresome task. Thus they have to (or at least should) find market niches. With the rise of China, we are also seeing more and more bold companies from the land of the dragon that try to rival their big Japanese (and smaller German) fellows. So far these companies tried to acquire a market share by either offering cheap products - which is perfectly Ok although probably not sustainable on the long term - or exotics designs. Many of the exotic designs are exceedingly fast lenses (f/0.95) which is, honestly, a rather doomed approach. The performance of such lenses is often dismal and, worse than that, they are extremely difficult to manufacture due to very tight tolerances. Manufacturing experience simply doesn't come out of the blue. Thus while this niche is not taken indeed, it is not the right place to be for a startup with limited production experience. So where to go then?
Laowa found a rather unusual answer to this - a "smooth trans focus" (STF) lens - namely the Laowa 105mm f/2 STF. STF lenses feature a apodization (APD) element (a concave neutral-gray tinted lens element) next to the aperture. The idea is to soften the bokeh (more on this later). This is certainly a smart move because to date only two (mainstream) lenses provide such a feature - the Sony 135mm f/2.8 STF and the Fujinon 56mm f/1.2 APD ... and we were thrilled by those! Despite almighty lens systems neither Canon nor Nikon are offering such lenses. Now there is a reason for this - phase-detection AF (DSLRs) just doesn't work with such a lens. However, for Laowa this comes handy because like most newcomers, they don't offer electronic coupling with their lenses anyway. Another consequence of the APD element is a decreased light transmission characteristic - you lose about 1 1/2 f-stops or in other words: it's a T/3.2 lens (T=transmission). The T-value does not change the original speed (min. depth-of-field) of the lens (=max f/2).
Some may be rather skeptical regarding the build quality of this lens but we are pleased to report that it is very impressive indeed. It is similar in build quality to -say- a Voigtlander lens. The Laowa is based an all-metal lens body with very smooth (dampened) focus and two aperture control rings. Yes, no typo there - unlike your average all-manual lens, the Laowa 105mm f/2 has two aperture rings. One conventional aperture control ring and a T-ring one which allows you to set the aperture steplessly between T/3.2 and T/8 - this controls a secondary aperture with 14 aperture blades. The lens does not extend during focusing and the front element doesn't rotate. A deep barrel-shaped lens hood is also part of the package.
The Laowa is a fully manual lens thus you can't control the aperture via the camera. Typically you are using Av-mode so despite showing you an aperture of f/0, the camera will determine the shutter speed according to the aperture setting. Needless to say but the more you stop down, the darker the viewfinder. EXIF data is also not produced.
Our test sample came with an attached "AF" chip (to activate the focus indicator in the viewfinder) but it didn't work on the EOS 5Ds R thus we had to remove it. If you'd like to have such kind of focus information, we rather suggest to go for the Nikon version of this lens and buy an Nikon-EOS adapter with AF chip - this is more future-proof because in the worst case you could simply exchange the adapter.
Note: The Nikon & Pentax versions of the lens feature a camera-controlled aperture coupling.
|Optical construction||11 elements in 8 groups inc. 1x APD, 3x LD and 1x XR element|
|Number of aperture blades||8 (f-stops), 14 (T-stops, stepless)|
|min. focus distance||0.9m (max. magnification ratio 1:6.25)|
|Filter size||67mm (non-rotating)|
|Hood||barrel-shaped, bayonet-mount, supplied|