Laowa 105mm f/2 STF Lens Review

Laowa 105mm f/2 T3.2 Smooth Trans Focus Handling and Features

The lens is a substantial one, manufactured using metal and intended to be extremely durable. It has 11 elements in 8 groups, including one HR (High Refractive Index), three LD (Low Dispersion), two floating elements and one special Apodization element. This last is a graduated neutral density element that becomes darker towards the edges, concentrating the light towards the centre of the frame and reducing or removing the Airy disc effects normally caused by diffraction. This is said to improve the bokeh, the quality of the out of focus areas, and leads Laowa to describe their new lens as “The Bokeh Dreamer”.

Hand in hand with this are two separate diaphragms. A conventional 8-bladed aperture controls the f/number in the usual way. Like the lens, which is manual focus only, this diaphragm needs to be stopped down manually to make a correctly exposed capture. The f/number relates to the physical aperture in the usual way, controlling exposure and depth of field.

The second diaphragm is a stepless 14-bladed manual design, marked in T stops, or Transmission stops. This actually gives the transmission value of a lens, the amount of light that actually reaches the sensor. This can be a different exposure to the f/stop, although in practice the two are considered the same in stills photography. In movie shooting, T stops are used, and the stepless diaphragm provided here is ideal for movie work. There are a limited number of T stops provided, from T/3.2 to T/8.

Either one or the other of these diaphragms is used, the unused one being left wide open. This does cause some handling issues, certainly on the Nikon D810 that was used for this review. The camera's exposure measurement was very unreliable with this lens and other methods, such as estimating exposure or even a separate meter, may be helpful. When using the f/stops, operating the stop down lever whilst manually focusing leaves the shutter release finger straining a bit to reach, but it does improve with practice. Using the T/stops is easier as the leaves stay at the position selected.

To complete the lens details, focusing is down to 0.9m (0.16x magnification), it weighs 745g and has a 67mm filter thread. The JJC lens hood provided is effective and bayonets on smoothly, but there is no click stop to keep it firmly in place. The lens is available, or shortly will be, in Canon, Nikon, Pentax K, Sony A and Sony FE fittings.

It will, of course, vary from camera body to camera body, but the Nikon D810 can be quite tricky to focus well with this particular lens. This means that we are slowed down. It could be ideal for portraiture, landscape and other fairly static subjects, rather than sports or wildlife. Despite at first being challenging in use, ways round it could soon be found and the lens proves to be rather satisfying to master.

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