Kowa Prominar MFT 8.5mm f/2.8 - Review / Lens Test Report
Lens Reviews - (Micro-)Four-Thirds

Review by Klaus Schroiff and Sebastian Milczanowski, published July 2015


"Kowa who?" - that's probably your first thought here I reckon. No, it's not another obscure manufacturer with a backyard workshop. Kowa is indeed a fairly big company with high quality optical products and quite some history behind them. Established in 1894(!) Kowa is a multinational Japanese company with almost 2000 employees and multiple product ranges and activities. In terms of optical products they are renowned for their spotting scopes, binoculars and industrial lenses. They even manufactured cameras till the late 1970s. The Kowa Six was their high profile product at the time - a medium format camera plus a large lineup of lenses. And it seems as if they are willing to try a comeback again. It all started a few years back when they introduced a -let's call it- hybrid lens - the Kowa Telephoto Lens Spotting scope which can be used both as a spotting scope as well as a super-tele lens for DSLRs. It even featured a fluorite crystal element - thus a super-expensive component also used by Canon in their very best lenses. Due to the lack of AF, it probably isn't an overly successful product but it seems as if they felt the wind of opportunity. Thus they just introduced a set of three new lenses for the Micro-Four-Thirds system which we'll all cover here at OpticalLimits. In this first review we'll discuss the Kowa Prominar MFT 8.5mm f/2.8 - thus an ultra-wide angle prime lens with a full format equivalence of "17mm".

It seems as if Kowa carved this lens from sheer rock (Leica style). It is very solid with a tightly assembled metal body - that's including the smoothly turning focus ring. By MFT standards it is a big lens and, consequently, also quite heavy. This isn't necessarily a bad thing though - bigger is often albeit not always better (in terms of optics). 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). While this will shy off some users, it is actually not a really big deal on a ultra-wide angle lens. The other specialty - or in this case it's more an oddity - is the filter thread. It is located on the lens hood. The bayonet mount is only meant to accept the lens hood. While we don't have a problem with this per se, it is worth to mention that the hood has a very large diameter of 86mm thus good quality filters are going to be a very expensive add-on. 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. It's not unattractive actually.

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. That being said the max. object magnification (1:12.5 at 0.2m) is fairly moderate.

Equiv. focal length17mm (full format equivalent)
Equiv. aperturef/5.6 (full format equivalent, in terms of depth-of-field)
Optical construction17 elements in 14 groups inc. 1xaspherical and 2xXD elements
Number of aperture blades9 (circular)
min. focus distance0.2m (1:12.5)
Dimensions (L x W)71.5x86.8mm
Filter size86mm (attached to the hood)
HoodPetal-shaped, bayonet mount, supplied
Other featuresFloating system, Dual Link Iris

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