CONTAX Planar G T* 45mm(Ms-optics)
Review of using a Kyocera CONTAX G-mount 45mm F2 lens modified by MS-Optics (Miyazaki Kogaku) to Leica M mount with Leica M digital camera.
Table of contents
Gallery
- CONTAX G Planar 45mm F2 Photo example (with LEICA M-P)
Review
The Planar 35mm wide-angle lens for the Kyocera/Contax G series was released at the same time as the CONTAX G2. The lens we are introducing is a CONTAX G AF lens that has been modified to a Leica M mount (rangefinder linked) by MS-Optics.
Part of the lens barrel of this lens uses a common helicoid called MS-35 developed by Ms-optics. The MS-35 Helicoid I own is an older model, and the angle at the base of the lens is shallow, making it difficult to get my fingers on the lens, making it extremely difficult to attach and remove the lens.
The MS-35 was designed to be used as a very small lens for compact cameras like the C-TESS, and it seems that they did not anticipate that the lens barrel would be as large as this lens. The MS-45 used in the Planar 45mm F2, introduced on a separate page, has a right-angled lens base and a reasonable width, so you won’t have any trouble attaching or removing the lens. I learned that the new helicoid MS-35 had an improved base, so I asked Ms-optics to change the helicoid part. However, the owner, Mr. Miyazaki, told me that it would be impossible to replace the helicoid in the modified lens due to the structure of the lens, so I gave up.
It is a specification of MS-Optics lenses that there is no click stop on the lens aperture.
Since it is a planar format, the rear lens element and the mount surface are in almost the same position, so there are fewer problems when using it with a variety of cameras. When using CONTAX G1/G2’s AF, the focus position was questionable when the aperture was wide open, so I often had to stop it down a little.
After changing from CONTAX G1/G2 to an M-mount rangefinder camera as my main camera, I had become estranged from CONTAX G lenses.
After getting a modified version of the Planar G 45mm with M mount, I started converting my existing G mount lenses to M mount using Ms-optics.
Since it has been changed to Leica M mount, it can also be used with various mirrorless cameras by using a mount adapter.
M-mount modification of this lens is widely practiced overseas, and some manufacturers sell not only modified lenses but also Helicoid lenses, which users can modify themselves. For details, please refer to the reference link website.
Specification
| Name | HOLOGON | BIOGON | BIOGON | PLANAR | PLANAR | SONNAR | VARIO SONNAR |
| Focal length(mm) | 16.5 | 21 | 28 | 35 | 45 | 90 | 35-70 |
| Max aperture | 8(fixed) | 2.8 | ← | 2 | ← | 2.8 | 3.5-5.6 |
| Min aperture | 16(Attached filter) | 22 | ← | 16 | ← | 22 | ← |
| Lens Construction | 5elements in 3groups | 9elements in 7groups | 7elements in 5groups | ← | 6eleme0nts in 4group | 5elements in 4groups | 13elements in 8groups |
| Min distance(m) | 0.3 | 0.5 | 0.5 0.8(*2)← | 0.5 | ← | 1.0 | ← |
| Lens length(mm) | 11 | 35.5 | 30.5 | 31.5 | 38.5 | 63.0 | 54.0 |
| Max diameter(mm) | 57 | 59 | 56 | 56 | 56 | 56 | 60 |
| Filter size(mm) | – Dedicated ND filters are available. Changes to f/8 > 16 to alleviate peripheral light attenuation. | 55 | 46 | 46 | 46 | 46 | 46 |
| Weight(g) | 120 | 200 | 150 | 160 | 190 | 240 | 290 |
| Weight(g) M-mount | 124 | 151 | 194 (222)*1 | 115 | 161 | 219 (259)*1 | – |
| Release date | 1994 | 1996 | 1994 | 1996 | 1994 | 1994 | 1999 |
*2: Minimum focus distance of AVENON modified lens
Reference links
- Zeiss Photography Historical Products (There is a data sheet for the CONTAX G lenses in the middle of the linked page.)
- Website of FUNLEADER (Website of FUNLEADER, which sells modified lenses and helicoids for modification)
- Zeiss PLANAR description page by Wikipedia
Update history
- 2024.02.16:Update article
- 2022.03.03:First draft
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