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.

Please see the disclaimer regarding advertising here.
Italicized links in the text are advertisement links that take you to other sites.

Gallery
Review
Specification and more
Reference links

Gallery

The photo example taken with LEICA S typ007

1．Overview

The downside of using the Mutar x1.4 T* is that the lens aperture becomes one stop darker.

Only the three lenses mentioned above can be used. With the Sonnar 140mm, the focal length (140mm x 1.4 = 196mm) changes from 2.8 to 4 when the teleconverter is attached, almost overlapping with the Sonnar 210mm. As of 2024, the Sonnar 210mm is an unpopular lens, and its price has plummeted to the point where good-quality used examples can be found for around ¥30,000. Therefore, there’s little need to attach the Sonnar 140mm to the Mutar x1.4.

As such, this teleconverter is essentially a teleconverter for use with the Sonnar 210mm and the Tele-Apo-Tessar 350mm. Since I don’t own the Tele-Apo-Tessar 350mm, I use it exclusively with the Sonnar 210mm.

2．Usability

The Mutar x1.4 T* is a lens teleconverter (hereafter referred to as teleconverter) that multiplies the focal length of the Contax 645 lenses: Sonnar 140mm, Sonnar 210mm, and Tele-Apotessar 350mm by 1.4.

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 the teleconverter. Overall, I think it’s an excellent teleconverter.

Due to the limitations of 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. The median price is around ¥20,000.

My impression after using it was that attaching a 1.4 teleconverter to a 140mm doesn’t dramatically change the shooting range, and I felt that cropping might be sufficient with a high-resolution camera.

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 mentioned earlier that it’s almost useless, but this time I checked the performance change when attached to a 140mm lens. I would have liked to bring the 210mm lens with me and compare the three, but since it would be too heavy to carry them all, I decided not to.

Lens name	Mutar
Focal length(mm)	x1.4
Max aperture	It becomes half a step darker than the attached lens.
Min aperture	It becomes half a step darker than the attached lens.
Lens Construction	7 elements in 5 groups
Min distance(m)	Same as attached lens
Lens length(mm)	41
Max diameter(mm)	82
Filter Size(mm)	–
Weight(g)	510
Release date	1999

The performance changes when a teleconverter is installed 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

Reference links

Affiliate Link

Update history

2023.07.16:Update article
2024.03.04:Update article
2023.06.25:First draft