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Kowa Prominar 8.5mm f/2.8 Micro Four Thirds Review

John Riley reviews the Kowa Prominar 8.5mm f/2.8 ultra wide-angle lens for Micro Four Thirds cameras, with manual focus.

|  Kowa Prominar 8.5mm f/2.8 in Interchangeable Lenses
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Handling and Features
Kowa Prominar 8,5mm F2,8 Front Oblique View

Kowa is indeed a venerable name in the world of photography, having produced many cameras and lenses from 1954 to 1978, plus more recently spotting scopes and even a range of ultra-telephoto lenses. The Prominar lens name has been used extensively and now we see it reappear in a series of three compact prime lenses for MFT format. We are looking first at the Prominar 8.5mm f/2.8 (T3) lens, and to follow will be reviews of the 12mm f/1.8 and 25mm f/1.8. The lens looks good on the Panasonic Lumix G6 camera body, so let's see how it performs and handles and if it lives up to its distinguished heritage.

Kowa Prominar 8.5mm f/2.8 Handling and Features

Kowa Prominar 8,5mm F2,8 Top View With T Stops

The lens may be compact, but it has a satisfying 440g weight that helps to give a quality feel. The generously sized lens hood is, unusually, held in place by a locking screw rather than the usual bayonet fit. This is simple and effective, albeit looking slightly strange with the bright chrome screw jutting out from the rim of the hood. As the hood just pushes into place we do need to align the marks carefully to avoid vignetting. There is ample room to insert filters into the 86mm thread which is part of the hood.

The focusing ring has very sculpted and hard ribbing to ensure a good grip, helping to maintain the vintage look of the lens as a whole. The lens is manual focus only, and as the 8.5mm equates to a 35mm-format 17mm equivalent here we find the one glaring omission that would make life considerably easier. There is no depth of field scale, although there are ample distances marked in feet and meters to make this a useful possibility. As the lens is very difficult to focus by eye, despite any focus assist features in the camera, a DOF scale would be incredibly useful. The focusing and aperture rings move in the direction of Canon cameras, rather than Nikon/Pentax which move in the opposite way.

Focusing is down to 0.2m, just under 8 inches, which represents a maximum magnification of 0.08x, or 1:12.5. This is reasonably close, but not exceptionally so.

Finally, we have the aperture ring, with a design that is very intelligent indeed. The review setting used was f/stops, which are provided with firm, positive click stops at full stop intervals, although one-third stops are quite easy to approximate. Pressing a small button enables the whole ring to be rotated through 180 degrees to bring into play the T stop settings. The T stops, usually used for movie shooting, are clickless. The whole idea is highly inventive and works beautifully.

Kowa Prominar 8,5mm F2,8 With Hood On Lumix G6

Lens construction is 17 elements in 14 groups, with 1 Aspherical and 2 XD (Extra Low Dispersion). The aperture comprises 9 circular blades, a feature used to enhance the bokeh of the lens.

There is considerable depth of field in a lens such as this, especially on MFT format, and the one handling issue, as mentioned above, is the lack of a depth of field scale to assist with this. With the G6 focusing is really very difficult and for the closer shots on a tripod, one answer is to use a retractable steel rule to physically measure distances. The success of this does depend on the accuracy of the distance scale on the lens, and this seems to be close enough to work well.

Notwithstanding all this, for more distant shots focus position is moot as with a modest aperture and setting close to infinity most things will be rendered sharply. The ultra wide field of view makes this an exciting lens to use, and there are huge creative possibilities.

Kowa Prominar 8,5mm F2,8 Rear Oblique View

Kowa Prominar 8.5mm f/2.8 Performance

Centrally, sharpness is excellent at f/2.8, pushing into being outstanding at f/4 and f/5.6. It is again excellent at f/8 and f/11 and still very good at f/16. All apertures are fully usable. 

The edges start of with good sharpness at f/2.8, rising to very good from f/4 through to f/8. Results are still good at f/11, but starting to soften at f/16. This is a very satisfactory result with such a wide lens.

Kowa Prominar 8.5mm f/2.8 MTF Charts

How to read our MTF charts

The blue column represents readings from the centre of the picture frame at the various apertures and the green is from the edges.

The scale on the left side is an indication of actual image resolution as LW/PH and is described in detail above. The taller the column, the better the lens performance.

For this review, the lens was tested on a Panasonic Lumix G6 using Imatest.

CA (Chromatic Aberration) is very well controlled, being held centrally to under half a pixel through most of the aperture range. At the edges the figure hovers around 1 pixel, but this is also an excellent result for an ultra-wide lens. Any further correction can be made using software, or indeed by switching on corrections in camera.


Kowa Prominar 8.5mm f/2.8 Chromatic Aberration Charts

How to read our CA charts

Chromatic aberration (CA) is the lens' inability to focus on the sensor or film all colours of visible light at the same point. Severe chromatic aberration gives a noticeable fringing or a halo effect around sharp edges within the picture. It can be cured in software.

Apochromatic lenses have special lens elements (aspheric, extra-low dispersion etc) to minimize the problem, hence they usually cost more.

For this review, the lens was tested on a Panasonic Lumix G6 using Imatest.

Interestingly, Kowa provides a distortion figure and they quote -0.12% barrel distortion. The measured figure is -0.22% but in any event, this is a very low amount of distortion and architectural images show no obvious sign of bending at the edges. 

Flare can be induced with the sun just in frame, but there is no real reduction in contrast, just the creation of artefacts in the image. Even this is not a major issue as the position of the lens to the light can be adjusted easily to remove the flare spots.

Bokeh, the quality of the out of focus areas, is not really much of an issue with an ultra-wide lens. Actually getting out of focus areas is more of an issue.

Overall, a very consistent and impressive performance that ensures high-quality results.

Kowa Prominar 8.5mm f/2.8 Sample Photos


Kowa Prominar 8.5mm f/2.8 Aperture range


Value For Money

The Kowa Prominar 8.5mm f/2.8 lens is priced at £749. An alternative might be the Venus Laowa 7.5mm f/2 lens, priced at £499. These are the only rectilinear ultra-wide prime lens available in MFT fit, so we have to look at zoom lenses to find a similar wide angle experience.

Panasonic Lumix G Vario 7-14mm f/4, £739
Leica DG Vario-Elmarit 8-18mm f/2.8-4 ASPH, £1049
Olympus M.Zuiko Digital ED 9-18mm f/4-5.6, £469
Olympus M.Zuiko Digital ED 7-14mm f/2.8 PRO, £949

Considering its features and quality, this makes the Kowa lens fair value for money. For more options have a look at the Top 35 Best Micro Four Thirds Lenses.


Kowa Prominar 8.5mm f/2.8 Verdict

The Kowa Prominar 8.5mm f/2.8 is a classy looking lens, it's beautifully made and the results are excellent. AF would make focusing much easier, but it can be worked around and still leave the lens being very satisfying to use. At least with the large amount of depth of field available there is some leeway at longer distances. 

In summary, it's a great lens that is delightful in use and delivers the goods.

Kowa Prominar 8.5mm f/2.8 Pros

  • Outstanding central sharpness
  • Excellent overall results
  • Low distortion
  • Low CA
  • No flare
  • High quality of manufacture
  • Creative potential
  • Pleasant bokeh

Kowa Prominar 8.5mm f/2.8 Cons

  • Manual focusing can be tricky
  • No weather resistance
  • No depth of field scale

Overall Verdict

Kowa Prominar 8.5mm f/2.8 Specifications

Lens Mounts
  • Panasonic Micro Four Thirds
  • Olympus Micro Four Thirds
Focal Length8.5mm
Angle of ViewNo Data
Max Aperturef/2.8
Min Aperturef/16
Filter Size85mm
35mm equivalent17mm
Internal focusingNo Data
Maximum magnification0.08x
Min Focus20cm
Box Contents
Box ContentsNo Data

View Full Product Details

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1 Mar 2018 11:03AM
My first SLR was a Kowa SE bought in 1966, so I was really interested to read John's good review of the Kowa lens. Notwithstanding the unreliability of my Kowa camera, I'm pleased to see the revival of the name.

Only one point I'd make. John states that, 'There is considerable depth of field in a lens such as this, especially on MFT format', but of course the DoF is format independent, and only focal length and aperture dependent.
1 Mar 2018 11:24AM
The point of the DOF comment is that although it is true that, say, a 50mm lens will always have the same DOF regardless of format, such a lens would be a standard lens on 35mm-format cameras. So for MFT format we would use a 25mm lens as a standard lens, which will have the DOF of a 25mm lens, in other words the smaller format has in this sense more DOF. In practice, we find this to be so. As an extreme example, a Minox subminiature format has a 15mm standard lens, and even at maximum aperture DOF from 9 inches to infinity.
1 Mar 2018 2:12PM
I agree with your mathematics that if we take a 'standard' lens' FoV then the MFT 25 mm will have greater DoF than the FF's 50 mm. But then again the 7-70 mm f/1.4 fitted to my Super 8 camera has exactly the same DoF on the tiny Super 8 frame at 50 mm as my 50/1.4 has on my A7RII.

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