Ms-Optics ISM 50mm F1.0 GA
Review and Photo example of the ISM 50mm F1.0.
Table of Contents
Gallery
- The sample photo were taken with the Leica M-P typ240
Review
1．Overview
ISM 50mm F1 GA is a large-aperture standard lens from MS-Optics (Miyazaki Optical).
As the GA in the lens name indicates, the lens format is a Gaussian type with 5 groups and 7 elements.
The minimum shooting distance is 0.8m, and it is linked to the rangefinder of a rangefinder camera over the entire range.
The overall length is 41mm, and the maximum diameter is 55mm. It weighs 180g, which is an exceptionally compact size and weight for a lens with an aperture of F1.0.
This lens has a large front element, so a 55mm filter can be used to protect the front of the lens, but the lens side has an external thread unique to Ms-optics (general lenses have internal threads), so the filter must be attached in the opposite direction to normal, so care must be taken. The hood also has an internal thread of 55mm diameter, so it cannot be attached to a normal lens.
2．Usability
The ISM 50mm F1 GA is a lens that lens designer Miyazaki gave up his Sonnar type to realize F1.0 as a standard lens, and realized it as a Gauss type.
Miyazaki’s ideal of a bright and compact lens is realized. However, the price is a hazy depiction and a decrease in contrast when the aperture is open. If you avoid opening the aperture and narrow the aperture, the large diameter lens becomes meaningless, which makes it difficult to use.
Also, at the open aperture of F1.0, it is difficult to focus at the desired position with the double image of a rangefinder camera, so when I used this lens most, I always had an EVF2 on my LEICA M-P.
When I used this lens with a LEICAS SL typ601, I was able to accurately determine the focus with a high-resolution EVF called EyeRes.
Mirrorless cameras in the 2020s have EVF display performance that is satisfactory regardless of the model you choose, so if you use this lens with an emphasis on the focus position, I think it is better to choose a camera with an EVF.
The sophisticated lens appearance represents the pinnacle of Ms-optics’s development.
It also comes in a wide range of colors, including the metallic green shown in the photo, as well as metallic red, metallic blue, metallic brown (gold), black paint, black, and silver.
3．Summary
In conclusion, to sum up the MS-ISM 50 GA, the design is quite over the top in order to achieve an aperture value of F=1, and the image quality at full aperture is questionable. If you plan to use a narrow aperture, there is little point in choosing this lens, and it is a lens for photographers who enjoy the wild image quality at full aperture.
Specifications and Competitor
There are a fair number of standard lenses for rangefinder cameras that are brighter than F1.0, released by manufacturers including Leica, Cosina’s Voigtlander, and Chinese manufacturers, and this lens is the most compact.
As mentioned above, there are some difficulties with the image quality at maximum aperture, so in terms of image quality at maximum aperture, the large-aperture standard lens Sonnetar 50mm / F1.1 released by Ms-optics has a straightforward image quality at maximum aperture and is easy to use.
| 項目 | MS-ISM | コニカ KM | キヤノン | ノクトン |
| 焦点距離(mm) | 50 | 50 | ← | ← |
| 最大絞り | 1.0 | 1.2 | 1.2 | 1.1 |
| 最小絞り | 16 | 16 | 22 | 16 |
| 絞り羽根 | 16 | 12 | 11 | 10 |
| レンズ構成 | 5群7枚 | 6群7枚 | 5群7枚 | 6群7枚 |
| 最短撮影距離(m) | 0.8 | 0.9 | 1.0 | 1.0 |
| レンズ長(mm) | 41 | 50 | 39 | 57.2 |
| レンズ最大径(mm) | 54.7 | 68.8 | 63 | 69.6 |
| フィルター径(mm) | 55 | 62 | 55 | 58 |
| 重量(g)・レンズのみ | 178 | 390 | 322 | 428 |
| マウント | M | KM | L39 | VM |
| リリース年 | 2019.08 | 2001 | 1956.09 | 2009.6.29 |
| 価格（定価・税別） | ¥150,000- | – | ¥60,000- | ¥131,250- |
Reference links
Update
- 2024.5.16:Update
- 2024.3.15:Update
- 2024.2.11:Update
- 2022.01.11:First draft
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- Amazon Affiliate link for Ms-optics
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