Three lenses are available: CONTAX 645 Mutar x1.4 T*

A review and sample photos using the Mutar 1.4x T* for the Contax 645 with compatible lenses and a Leica S Typ007.
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Table of contents

Gallery
The photo example taken with Three lenses are available: CONTAX 645 Mutar x1.4 T* and LEICA S typ007
Review


1.Overview
The Mutar x1.4 T* for CONTAX 645 is a teleconverter that can be used with CONTAX 645 telephoto lenses, extending the focal length by 1.4x. In exchange for extending the focal length, the lens aperture becomes one stop slower.
The three CONTAX 645 lenses that can be used with this converter are the Sonnar 140mm, Sonnar 210mm, and Tele-Apo-Tessar 350mm, and the performance changes are as follows:
master lens Focal length | master lens F value | Focal length after installing teleconverter | F value after installing teleconverter |
140mm | 2.8 | 196 | 4 |
210mm | 4 | 294 | 5.6 |
350mm | 4 | 490 | 5.6 |
2.Usability
The Mutar x1.4 T* for CONTAX 645 is a lens teleconverter (hereafter referred to as teleconverter) that increases the focal length of the CONTAX 645’s Sonnar 140mm, Sonnar 210mm, and Tele-Apo-Tessar 350mm lenses by 1.4 times.
When I checked the images at 100% magnification on a monitor, I could see that the resolution of detailed rendering was excellent even without the teleconverter, but the difference was slight. There was also almost no noticeable color bleeding caused by attaching the teleconverter. Overall, it is an excellent teleconverter.
Due to the limitations on compatible lenses, as of 2024, the Mutar x1.4 seems to be in considerable stock on the used market, with prices starting from around 10,000 yen.
The most practical use of the Mutar x1.4 T* for CONTAX 645 is when attached to the Sonnar 210mm, allowing it to be used as a lightweight 300mm f/5.6 lens.
When this teleconverter is attached to a Sonnar 140mm, the focal length becomes 140mm x 1.4 = 196mm, with an aperture of f/4. These are roughly the same specifications as the Sonnar 210mm f/4. If the Sonnar 210mm had maintained its price at about half its retail price, it would have been worthwhile to attach a teleconverter to extend the focal length. Unfortunately, the Sonnar 210mm f/4 was a lens that could be purchased for around ¥20,000 at its lowest, cheaper than the Mutar x1.4 T* for the CONTAX 645, so there is likely little demand for attaching it to a 140mm.
However, used lens prices fluctuate, so if the price of the Sonnar 210mm returns to normal, demand for attaching a teleconverter to a Sonnar 140mm may return.
The Tele Apotessar 350mm is thought to be designed to be sturdy, but having to sandwich a teleconverter between two heavy lenses is not a pleasant experience for users. Additionally, there are many concerns when using a medium format telephoto lens with a focal length of 490mm in the field, such as carrying it around and camera shake during use.
3.Summary
In conclusion, to sum up the Mutar x1.4 T* can be summarized as follows:
- This converter increases the focal length of the master lens by 1.4 times, but the downside is that the F-stop becomes one stop slower.
- It is compatible with three lenses: Sonnar 140mm, Sonnar 210mm, and Tele ApoTessar 350mm.
Specifications, considerations, etc.
I checked the changes in image quality when I attached the Mutar x1.4 T* for CONTAX 645 to the Sonnar 140mm. The changes in lens specifications are as follows:
Lens name | Mutar | SONNAR 140mm F2.8 | SONNAR 140mm F2.8 +Mutar 1.4 |
Focal length(mm) | x1.4 | 140 | 192 |
Max aperture | − | 2.8 | 4 |
Min aperture | − | 32 | 32 |
Aperture blade | 6 elements in 5 groups | 7 elements in 5 groups | 13 elements in 10 groups |
Lens Construction | – | ? | ? |
Min distance(m) | – | 1.3 | 1.3 |
Lens length(mm) | 41 | 98 | 139 |
Max diameter(mm) | 82 | 81 | 82 |
Filter Size(mm) | – | 72 | 72 |
Weight(g) | 510 | 688 | 1189 |
Lens hood | – | GB-73 | GB-73 |
Lens mount | CONTAX 645 | CONTAX 645 | CONTAX 645 |
Release date | 1999 | 1999 | 1999 |






Reference links
Affiliate links
- CONTAX645・Ads by ebay
- CONTAX 645 lens・Ads by ebay
- Leica 16038 S Adapter C Contax 645 Lens to S System・Ads by ebay
- Mutar x1.4 for CONTAX 645・Ads by ebay
- SONNAR 140mm for CONTAX 645・Ads by ebay
- SONNAR 210mm for CONTAX 645・Ads by ebay
- Tele Apotessar 350mm for CONTAX 645・Ads by ebay

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Update history
- 2025.9.23
- 2024.07.16:Update article
- 2024.03.04:Update article
- 2023.06.25:First draft
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