KOWA PROMINAR 12mm F1.8

Large aperture wide-angle lens for M43

A review and photo examples of the KOWA PROMINAR 12mm F1.8.

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Gallery

The sample photos were taken with a Panasonic DMC-GM5

Review

Overview
Usage
Add info

1．Overview

The Kowa Prominar 12mm is a Micro Four Thirds lens with a focal length of 12mm that was released by Kowa in 2016.In 35mm format, it has a focal length of 24mm.

The lens is made up of 12 elements in 10 groups, with aspherical and XD (low dispersion) lenses, a minimum shooting distance of 0.2m, and 9 aperture blades. The filter diameter is 72mm, and is attached by screwing it onto the front of the lens.

A dedicated flower-shaped lens hood is included; after attaching the hood to the lens, secure it in place by tightening the horizontal screw at the base of the hood.

The lens barrel is available in a variety of colors, including Kowa green, silver, and black, which are Kowa’s image colors.

12mm. Image taken from KOWA official website.

2．Usage

The lens barrel is large, so when it is attached to the small body of the LUMIX GM5, the lens is emphasized. However, since the barrel is made of aluminum, it is light for its size and weighs 440g.

At the maximum aperture of F1.8, vignetting and loss of resolution in the peripheral areas are seen. For portraits and dark scenes where you may want to use the maximum aperture, this negative effect becomes less noticeable by placing the subject near the center and making the peripheral areas dark.

During the day, narrowing the aperture to around F4 reduces vignetting and increases peripheral resolution.

Many Micro Four Thirds wide-angle lenses are distorted when shooting in Raw in order to make the barrel smaller, but this lens has a large body with a generous lens diameter and is designed to reduce optical distortion, so it takes quite good pictures of distant scenes.

This shows that even if the sensor size is small, a certain lens diameter is necessary to create a lens with high optical performance.

This applies to any lens, but when shooting a straight object at a distance of about 3m, distortion can be noticeable at the edges.

The lens hood is huge, so when I used it without the hood, there was no suspicious light even in backlit situations, so I think the lens coating is working.

Aluminum lens barrels are prone to scratches and dents. In particular, if the hood comes off when it is attached, scratches and dents can form where the hood comes into contact with the lens barrel. The hood is attached by fastening it with a side screw after fitting it in, so the hood can easily come off in a bag. Instead of using a side screw, the hood should be attached using a screw-in or bayonet method.
At present, there is no problem with backlight resistance, so it seems better not to use a hood.

3．Add info.

KOWA is the abbreviation for Kowa Co., Ltd., a company based in Aichi Prefecture, and if you look at the company’s website you will see that it has many affiliated companies. One of these companies, Kowa Optronics Co., Ltd., manufactures and sells imaging equipment, manufactures and sells this lens.

KOWA has released three types of lenses for Micro Four Thirds.

8.5mm F2.8 / 17mm
12mm F1.8 / 24mm
25mm F1.8 / 50mm

Kowa’s official release states that the 8.5mm and 12mm cannot be used with the LUMIX G1.
The reason is that the rear lens and the sensor come into contact. As you can see in the photo below, the wall in front of the G1’s sensor is angular, and it is thought that the rear lens would interfere with this. The wall in front of the sensor of the GH1 is carved out in a cone shape, and all Micro Four Thirds cameras since the GH1 have this shape.

DMC-G1 – Image taken from Panasonic official website

DMC-GH1 – Image taken from Panasonic official website

仕様

項目	8.5mm F2.8	12mm F1.8	25mm F1.8
焦点距離(mm)	8.5	12	25
35mm判換算	17	24	50
最大絞り	2.8	1.8	1.8
最小絞り	16	16	16
絞り羽根	9	9	9
レンズ構成	14群17枚	10群12枚	6群8枚
最短撮影距離(m)	0.2	0.2	0.25
レンズ長(mm)	87	91	94
レンズ最大径(mm)	72	77	60
フィルター径(mm)	86	72	55
重量(g)	440	475	400
リリース年	2014年9月20日	2015年2月6日	2015年2月6日
定価	￥116,000	￥109,000	￥89,000
備考	＊Panasonic製LUMIX DMC-G1にはご使用できません。	＊Panasonic製LUMIX DMC-G1、JVCケンウッド製GY-LS300にはご使用できません。