Kowa Prominar MFT 12mm f/1.8 - Review / Lens Test
Lens Reviews - (Micro-)Four-Thirds
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Review by Klaus Schroiff and Sebastian Milczanowski, published August 2015


Recently we reviewed the Kowa Prominar MFT 25mm f/1.8 and Kowa Prominar MFT 8.5mm f/2.8. The results were good to even impressive. So here's the final review of the last of the 3 initially released Kowa lenses for the Micro-Four-Thirds system - the Kowa Prominar MFT 12mm f/1.8 - thus a fast, wide-angle prime lens. Following the guidance of its cousins the pricing is a bit on the steep side again. A price tag of around a 1000US$ puts it into direct competition with the Olympus M.Zuiko 12mm f/2. Despite being a little faster, this is a difficult task ... again. Honestly it is a bit astounding that Kowa attempts to tackle the market at the very high end although the low production volume probably just doesn't make it possible to offer such lenses "made in Japan" at more affordable prices.

In terms of build quality, the Prominar 12mm f/1.8 remains in line with the 8.5mm f/2.8 and 25mm f/1.8 again. The lens body feels excellent thanks to a tightly assembled metal body and a smoothly turning focus ring. By MFT standards it is a big (to be precise: long) lens and, consequently, also quite heavy. Interestingly it has a couple of specialties that you don't find elsewhere. To begin with, it features a so-called "Dual Link Iris" which gives you the choice to select the aperture either in distinctive f-stop clicks (for photography) or in a smooth cine mode (T-value for movies). From this you can already conclude that the lens has no electronic coupling (no AF, no EXIF data, no camera-controlled aperture). However, at least it's usually fairly easy to focus a 12mm manually. The other specialty - or in this case it's more an oddity - is the filter thread. It is located on the (petal-shaped) lens hood (72mm). The bayonet mount is only meant to accept the lens hood. Furthermore you have the choice between three different colors - black, silver/black and green/black. The latter probably relates to a Kowa tradition because their spotting scope share the same color scheme.

As mentioned there is not much to report regarding the AF performance - because there is none. It is a fully manual lens. Apropos focus - the Kowa lens features a so-called floating system. Thus the positioning of the focus groups is optimized towards close focus distances. The max. object magnification (1:10 at 0.2m) is moderate but slightly better than on its Olympus counterpart.

Equiv. focal length24mm (full format equivalent)
Equiv. aperturef/3.6 (full format equivalent, in terms of depth-of-field)
Optical construction12 elements in 10 groups inc. 1xaspherical and 1xXD elements
Number of aperture blades9 (circular)
min. focus distance0.2m (1:10)
Dimensions (L x W)76.5x90.5mm
Filter size72mm (attached to the hood)
Hoodbarrel-shaped, bayonet mount, supplied
Other featuresFloating system, Dual Link Iris

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