CONTAX Planar 2/45 T*(GtoM)

This contents is a record 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

CONTAX G Planar 45mm F2 Photo example (with LEICA M-P)

The lens construction is a classic planar configuration with an old coating, which may cause fringing in backlit conditions, giving the lens an old lens feel.
Compared to 35mm lenses, the focal length is 10mm longer, which gives the lens a softer blurring effect. This may be due to the performance limitation of not being able to keep up with digital resolution, but it can be enjoyed as the unique flavor of the lens.
Naturally, there is no problem when using the lens with an EVF, but it can also be used with the viewfinder of the Leica M, as if it were a slightly larger 50mm frame.

I found this lens at a used camera shop in Shinbashi around 2007 and purchased it. The used lens I purchased was not properly fixed to the lens barrel and fell out of the helicoid. This was the beginning of a memorable relationship with Mr. Miyazaki, the individual builder of the lens.
I had used this lens for the G mount when I was using the Contax G1/G2 film cameras, so I knew that I was not dissatisfied with its performance on film. Since then, I have mainly used M-mount cameras, so I could not miss this lens in M-mount format.
Starting with the acquisition of this lens, I started to convert G-mount lenses to M-mount, such as the Planar 35mm, Biogon 28mm, Biogon 21mm, Horogon 16mm, and Sonar 90mm.
The M-mount modified lenses have since become readily available with the acquisition of a digital Leica, and although I have sold and bought other brands of M-mount lenses, I have kept them on hand and used them.
I checked the market for G-mount lenses for my affiliate and was surprised to see that lens prices have gone up. Lenses that could be purchased for around 20,000 yen for a 45mm lens at the end of the film camera era are now priced at around 50,000 yen, which shows the great demand for reuse of lenses by mirrorless cameras.

Since the lens has been converted to the Leica M mount, it can be used with various mirrorless cameras with the use of a mount adapter.
M-mount modification of this lens is widely practiced overseas, and some places sell not only the modified lens but also the helicoid alone (for details, see the Web site at the reference link).

AF lens for CONTAX G converted to Leica M mount (distance meter linked) at MS-Optics.
It uses a common helicoid called MS-45.
There is no click stop on the aperture, which is a specification of MS-Optics lenses, but depending on the shape of the aperture, it sometimes moves by itself in the camera bag.
In particular, the aperture of this lens is located at the thickest part of the front of the lens, and it is common for the position of the aperture to change when the lens is removed from the camera bag.
For this reason, it would be better if the aperture ring were a little stiffer.

focal length(mm)45
Maximum aperture2
Minimum aperture16
Lens configuration5groups 7elements(Planar-Type)
Minimum distance(m)0.5Works with the camera’s rangefinder from 0.8m to infinity.
Lens length(mm)40
Lens max diameter(mm)47.4
Filter diameter(mm)46
Planar 45mm lens configuration for CONTAX G (scanned and traced from the lens manual)



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